Besides Perna it seems like everyone else has the right idea. If you were uncomfortable and you said no but she either talked you into it (even if you still didn't want to) or forced you that is illegal.

Stay away from this person; if she's in your classes or something tell your teacher to help you keep your distance.

No one ever deserves to be forced to do anything. The situation and circumstances don't matter. If you say no or you are uncomfortable or you "don't think" it's a good idea then the other person must back off and there's no excuse to continue try to change your mind.

This is not your fault!!!!