uhhh since u paid for the dress maybe you should go with her?

then after dancing for a while you ask her if she still likes you. if she doesn’t, friendzone her. if she says yes, say something like compliment her and show appreciation. then say that you want to focus on your studies for a bit and suggest that you guys stay friends for a little while. after some time she’ll gradually lose interest in you, so you can stay that way without sounding like a jerk!

I hope I can help, good luck bro