hello there!

I'm a 29-year-old man from Brazil and I'd really appreciate some help with my current situation... I am going to be completetly blunt here, pardon me if I come off as being arrogant or anything, I have no reason to do that, I just want to be as clear as possible about who I am and what my situation is... it's also gonna be kind of a long write up, but I really need the help, so, please, bear with me...

recently I was just minding my business on facebook when I saw a friend of mine post a picture with 2 girls, one of which immediately caught my attention and that got me instantly attracted to her; and like a true "smooth operator" I just reacted to the post with a simple "like" and went on with my day... Even though I didn't know her, somehow I knew she'd notice that "simple like" and get curious about me, "stalk" my profile a bit and probably end up sending me a friend request or something like that, and that is exactly what proceeded to happen (I usually am very good at telling which woman is going to get attracted to me just by looking at her and studying her behavior)... needless to say I was very excited about that, but still I kept my cool and waited a bit before starting a conversation... fast forward a couple of days and I finally do it... all of a sudden we're talking non-stop and getting along great (via "facebook messenger"), she seems enthusiastic and excited about meeting me and things are going as good as expected, but with those conversations came the first red flag: she is 10 freakin' years younger than me (19) and I'm not exactly used to such an age difference, but that didn't trump the fact that I felt completetly attracted to her, so I kept on keeping on... on the very next (sun)day night I was riding my skateboard aound the city and stopped to have a breather and get a bottle of water in front of a local business (bar), and, to my surprise, when I looked to the left there she was walking the pavement alongside another guy (who hates my guts, but not because of her [I didn't even know she existed a few days before], but because of the fact that we're completely opposites, he's a narcisistic liar who talks and acts annoyingly loud and I'm and I'm a stoic, skeptic, observant, no-bullshit, no small-talk truthseeker...), she noticed me right away when she was near, looked me right in the eye with a half-smile. without saying a word, and I did the same; she even twisted her neck over his shoulder to keep looking for a couple of seconds... right after that (when she'd already passed and they had their back to me) she looked at him grabbed him by the hand in a very, very insecure manner, like she was afraid of him knowing that she had noticed me... needless to say that for me that was it, I immediately stopped reaching her and left her get on with her life, I don't like standing in the middle of crossfire, after all...

about half a week later she contacted me again on facebook messenger, trying to maintain a conversation... I knew she was interested but I also knew she had something else with another person, so I kept my distance and only replied in a polite (but short) manner... at some point in the conversation she said something (I can't remember exactly what) that led me to tell her I saw her that day on the streets and noticed how she looked at me, she obviously denied it, I knew it was bullshit, but still didn't try to reach in and kept my cool and was like "alright!"... at some point I mentioned that I noticed that she looked me right in the eyes and then grabbed him by the hand very insecurely and she was like "wow, you're REALLY good at reading people..." (which is actually true). next thing you know she's telling me how much she's frustrated with her relationship, that she's feeling used and wants more than just to date someone who doesn't treat and/or present her as his girlfriend, I try to advise her, she tells me almost everything about it, I keep responding politely, giving attention but not entirely showing I am fazed by the fact she has another person... on the very next day she contacts me again and asks for my phone number (whatsapp), I promptly give it to her and she starts to engage in a more intimate conversation with me via whatsapp... by then I was like "fuck it, I'm not gonna repress my desires anymore", so I started to engage more actively in the conversation and that strategy paid off very quickly, by the night she was already sending me a bunch of photos, asking me to send audios and pics and we're getting along great, attraction from both sides is very clearly happening at this point... all of a sudden she starts sending me "nudes", telling me she wants me BAD, teasing me and telling me she wants to do all kind of kinky stuff (which I fully appreciate, LOL), and of course that hooked me right in and I was eagerly responding (even though I didn't send one single "nude" back)... needless to say things got HOT very fast and the next step was as easy as a pie, she asked me to go out with her on a sunday afternoon alongisde a couple of friends (she has and lives with very conservative parents). when she first saw me she hugged me like I was a loved one she hadn't seen in a long time, and the afternoon was great, we got along even better than via chat and her body language told me everything I needed to know, she couldn't keep from touching me, from engaging in physical "jokes" and even jokingly "attacking" me from time to time, but I usually don't try to make out for the first time in front of others, so we didn't actually do it until we were alone and she was leaving by the end of the day (a very hot kiss and a rib-breaking hug followed by me smelling her neck, which led hear to almost lose it (LOL)... then she was gone with a smile on her face and I was left wanting her even more...

next day she kept reaching me and teasing me, saying everything she wants to do with me ("I wanna sit on your face, you bastard! LOL"), so things kept getting hotter and hotter, I knew every part of her body before even getting her naked in front of me, it got to the point that I was starting to feel very anxious by the accumulated energy... so I started to ask her out again, but then something I should have mentioned before started to get in the way: she's one of those depressed beautiful girls, I even suspect she has some hints of "histrionic personality disorder", she complains about her mother not loving her, has a tendency of lying (and is seemingly very good at that to other, but not to me, narcisistic/histrionic people are usually very shallow and my IQ is too high for that, I usually understand patterns very quicly and also have a sensitive/observant side that can read even the best actors out there) loves attention and loves to be desired... she likes to say she tried to kill herself multiple times, that life sucks, that she can't stand it anymore and such bullshit, and that took me back to my ex-girlfriend, who was EXACTLY like that (professionally diagnosed as being a sociopath, although I think she didn't tell the "exhibitionist/seductive towards everyone, even those she doesn't want and friendzones" part of her personality to her analyst, [she used to get very defensive when I confronted her about it] which'd make her more of a histrionic person badly diagnosed with antissocial disorder) and almost made me go crazy, imagine having a 5-year relationship with a bipolar, histrionic, stunningly beautiful girl who likes sex as much and as kinky as I do, it took me a long time to recover from that (especially because we kept meeting from time to time after the end of the relationship)... so that pushed me back a little, but still I didn't stop talking to her, I was already completely hooked... I instead managed to get her good side back up again and we proceeded to talk life before... two days later we met in front of her course and made out instantly, things got CRAZY very quickly, but she had to go to class and I didn't wanna make her skip it because of me (tryna be the mature one, you know), so I had to let her go... while in class she started messaging me, saying that she was confused, that she enjoyed so much kissing me that she was feeling bad about "betraying/cheatin on" her non-official boyfriend (who is a piece of shit with her, to the point he refuses to wear condoms and she even told me she was afraid of being pregnant and the guy didn't give a crap about it, treated it like it was just something funny)... well, needless to say that threw me the fuck off, but after class I agreed to meet her and we talked about the issue... she cried, she hugged me, all of those things women do when they're emotionally confused, I tried to open her eyes about who she was dating (I swear I wasn't playing for my team there, I was just being completely honest because I know the guy way better than she does) her bus arrived and she kissed me on the cheek and left... unfortunately that messed my game up, I was already feeling kind of attached to her (mostly phisically, but when you spend a lot of time avoiding the kind of people that most attract you in fear of getting hurt again that can be confused with feelings, and she is so, so similar both phisically and mentally to the woman I used to love it's not even funny [even though she's 9 years younger]), and I kept trying to talk about the issue she brought up, searching for explanations as the racional motherfucker I usually am (mistankenly sometimes, not everything can be argued about). but even though I made that mistake once, that didn't change her attitude towards me, so we kept building that fire...

we kept talking about meeting again but she started claiming she was having issues with her parents and couldn't leave her house (which to be fair the had mentioned before, it's something about her drinking alcohol; which I don't, to be clear) whenever she wants, which I completetly understood. last saturday she finally said she was gonna break up with her non-boyfriend and she actually did, even showed me the conversation (I didn't ask to, I don't like being the inconvenient, needy one), so I started thinking she was falling for me and got even more anxious... on sunday she was already saying she was talking about me to her parents, asked me to say hello via audio and everything, and said she wanted to be my girlfriend, we kinda reached a verbal agreement and things went on getting more involving, by this point she was already saying she likes me a lot (never love), sending cute heart emoticons and everything, and said me she was gonna come to visit me and fuck my brains out on monday, which got me very excited and raised my expectations (mistake!)...

we had a very "cute" and "hot" chat on that day, we were already looking like a couple and I was getting emotionally involved, but, of course, her "bad side" came up again, but instead of being cool and trying to understand her and lift her spirit again I fell right into her freakin' trap and started kind of pressing her, saying I wanted to see her, saying the other guy doesn't deserve her, and I think that kind of threw her off... she didn't stop talking with me, but she didn't come to see me on monday and the last couple of days things cooled off a bit (I repeated the mistake of trying to talk about feelings a couple of times over), so I got very frustrated, I wanna fuck her brains out, I don't know if I can approach anyone else before doing that shit (that may sound a little too proud, but I don't care), and I KNOW that if we do that she's gonna get hooked up immediately, I'm very confident in my abilities and my "hard work" on that area, and she even told me her "other" is not very good at making her cum and rarely even touches her clit... but I messed up, I've shown my weaknesses, I have made myself very present all the time and didn't give her time to miss me, I was even kind of selfish in not considering the unresolved feelings she has for the other guy and engaged in conversations about feelings and about us and that made her change her attitude, she told me to stop but I was so anxious about seeing and FUCKING HER that I just couldn't, so it got to the point that she stopped having "hot conversations with me", even though she still tells me she wants me (without me asking it, I wouldn't do that)... yesterday it got to the worse point and I got sick of it and gave her an ultimatum: "ok, I see that you're not as interested as before, so I wanna tell you that even though I like you I like myself more, that I really hope you get well and find your way, but I'm OUT!", and I was really out and stopped messaging her, even disabled the wifi on my cellphone so I wouldn't even receive her messages and possibly fall into the temptation of answering and pandering to her feelings again... eventually I did read the messages she left after I said my piece and she had two reactions: first she told me she didn't wanna hurt me, but she still wanted me bad and was still planning to see me, but then she freaked out when I didn't respond, told me she likes me a lot but still has feelings for her recent non-boyfriend and that it's probably better for us to eventually date without getting attached... after that I responded, stopped talking about what threw her off and started all again, but things didn't get as hot as before, she kept responding me but not as eagerly, still saying she wants me but I don't know what to think now, last time I talked to her she went to sleep, so now I decided to take my distance and keep my cool...

my question is: what should I do? should I let her miss me and approach me? should I forget about it? I wanna fuck the shit out of her, I really like her but I'm not exactly in love, so I think it would be a fun time for both of us... do you guys think she likes me and is just confused? I didn't contact her today... (and, look, she just sent a photo on whatsapp, should I respond?).

I appreciate any help, sorry for the loooong text, but I really needed to get it off... THANK YOU!

EDIT: not talking to her all day kind of worked and we ended up meeting again after the contacted me just an hour ago in the same place as before and made out again, I tried to ask her to my house but she refused, claiming she had an exam... so I came back home (I live like 200m from her course).

EDIT 2: it's been almost a week since then and we haven't seen each other anymore, I've tried all sorts of things but one things I haven't done is stop giving her attention... things is: she stopped being seductive towards me, says she wants to be my friend but when I confront her about it she says she just doesn't wanna hurt me but also doesn't want me to leave her hanging... WHAT THE FUCK? also everytime I try to talk about "US" she gets kind of turned off... should I just drop it and hope she freakin' misses me?

PS: I wanna make it clear that I don't wanna hurt this girl, I would never make her have feelings for me, fuck her and then leave her hanging, I'm not like that, I'm usually a very fair-minded and faithful guy, but I'm also a horny motherfucker who wants to get back the years I've spent after someone who didn't give a shit about me... if this girl were to be in love with me I'd probably correspond and treat her as good as she deserved... the only thing that usually makes me wanna get out of relationships is bad sex and lies... the rest I can manage... so please don't think I'm trying to elude this girl into loving me just so I can fuck her, it's not that at all, it's just that the desire of having sex with her is what's making me anxious...

TL DR: having problems with how to act towards a girl who's been shit testing me for weeks now, would appreciate any help whatsoever... how could I maintain a stronger frame?