Only found TRP community last week and after reading, I realize most of my mistakes but I thought hearing some opinions will reassure me of what I did wrong, how to improve, and finally move on. I'll try to make it short:

3 months ago I begin talking to a 19 year old close family "friend". I (23) have known her my whole life but we begin texting after a family gathering. We talk for 3 weeks non-stop, flirting, phone calls, pictures and presumably develop feelings. Hang out, make out. Then I travel for two weeks to Colombia, so day before I leave she comes over and we have sex for first time. Have a pregnancy scare. Whole time abroad, we talk everyday. I come back, and we pick up where we left off. We're both in college, and see each other when we can. But then I notice she becomes less engaging, flirting more or less ceases, literally avoids certain questions, sometimes doesn't respond to texts, blows off texts asking to go on a 'date' twice, and says she's busy. I start to worry because she never offers to see me and I always ask to see her. While all this is happening, we still do manage to see each other about 4 times but only in her car, or mine. And each time we would just talk, oral sex, or fuck around. From the beginning though, I made it a point not to act as needy as possible (even though I felt like it) I didn't respond to her texts immediately, no double text when she doesn't respond for a whole day, sometimes not text her first, and never ask why she can't see me or what she's doing. But I can't say her not responding and give excuses like "my phone died a long time ago", "sorry I was busy" didn't bother me. I did the same to her. But everytime I would, she would double text, ask why I'm not talking to her, etc. The last time we ever hang out is in car she asks to go through my phone. I want to see what she does so I let her go through my contacts. She then asks to see my photos and I say no. She says sorry she's really jealous and I let it go. Confused about all the mixed signals and tired of the games, a mutual friend and I find her Instagram. Mutual friend tells me her abusive ex boyfriend's name and we believe we find his profile. They follow each other. I now think the worst of this person. In an effort to act normal, I send her a meme one morning and ask how she's recovering. She texts me '82nd Ave' - the train stop to her house. Text her "Wrong person hun lmao" and she doesn't respond until 2AM with a "Goodnight". I pretend nothing's wrong for the next days, then I foolishly ask her to see me because we need to talk, she agrees, day comes and she bails. I respond with a long angry text telling her everything I felt, about her lying, what I knew about her ex, etc. She says I'm wrong, is offended, and talks about how hard she works in school, doesn't need people like me in her life, and doesn't have issues. I respond and so does she and we leave it like that for a week. During that week I found out that profile of her "abusive ex boyfriend" wasn't actually her ex. I felt like an idiot because that was a big argument I had as to why I ended things with her. In an effort to make her think I'm not crazy, I text her I know I was wrong about that, sorry about it, and to meet up to let me explain and end things amicably for the sake of the family we share. I wasn't asking to get back together but she thought I was. She says leave it like that, that she liked me, I insulted her too bad, and she can't give me the time I'm looking for. I insist again it's just to talk but no response. So I text her that I'll let it go now.

My only questions: What did I do wrong? What did I do right? Did I break it off for the wrong reason? What do I do next, if anything? (I ask this because I will still be seeing this person in the future. Probably for years to come.)