Hot/cold

I truly don't understand this girl. This girl is a junior, and I',m a senior. Next year Ill be going to college, but I really want to be wit this girl before, and during college. It's been on and off for a while, and now she wants to hang out and repeatly asks me to come over. It's been hard as I've been going through many girls to get over this one who I can't get over. She recently asks me to come over and then I say "sure when? this weekend?" she turns around and says we'll have to see. I know it's prom weekend, but I know she's not going. I'm stumped.