Alright, so a little background first: I'm a sophomore at university, this girl is a freshman. We met a couple months ago, and have been dating for a month and a half; we're not in an exclusive relationship at this time.

At first, we were meeting up a lot, and doing what you think of as date activities (going out to dinner, seeing movies, going for walks), and also having sex. The past few weeks have toned down to once or twice on the weekends (as we get closer to finals and deadlines for the semester).

All of the dates happened when I proposed a time and place. In the past two weeks though, I'd suggest something, and she'd turn it down and wouldn't suggest another time. Me being stupid would ask about another time ("Well how about X day?"), and she'd say yes to that. Then we'd meet up, walk a bit, and then go back to one of our places and have sex. This upcoming Saturday, we're going to a ball -- real formal black-tie affair -- I invited her a couple weeks ago, as I know how to ballroom dance and would like a date, and she said sure. She bought a dress and has brought it up a couple times, excitedly. But I feel like I might be starting to be used here. So I texted her this weekend:

(Yesterday) Me: "Come over tonight and we'll finish 'We're the Millers'" (We'd been talking the night before about her wanting to see the ending to it)

Her: "Tired"

Me: "Okay." (I didn't propose another date because this had been going for the past week, and I was over it)

(Today)

Me: "Do you want to hang out tonight?"

Her: "No can't sorry"

Me: "Okay, do you still want to go to the ball on Saturday?"

Her: "Yes"

Me: "In that case, I'll meet you Friday night. We have some things to discuss."

Her: "Lol some things to discuss?"

Me: "Yep, see you then."

Now I've been thinking about what I should actually say, whether or should say it at all, or how I should say it. Here's what I've got right now:

I get you want to go to the ball with me, and that's great. I want a date to the ball. But I don't want an escort. When I suggest us hanging out together, you turn it down, and don't offer an alternative time. I'm suspecting that I'm right when I say that you don't want to hang out with me, and that you're doing this so you have an excuse to doll up on Saturday and have a hot guy to match your shoes and purse. Bottom line is, I have better ways to occupy my time than with someone who doesn't want to be a part of my world.

That's all I've got. Is it even worth talking to her? Should I just drop her and not talk at all? Advice on what I'm planning on saying?