just turned 18 a few days ago, and am a senior, also get a lot of girls haha, heres my advice....
1. dont ask her out yet
2. She wants to have some sort of friendship with you before you date, so work on that and shell start liking you even more
3. Text her, a lot, ask tons of questions ABOUT HER (most important part).
4. Dont give a lot of compliments, give some but never like overly affectionate.
Follow those steps until a few days before the dance, and you do it right she will want you to ask he rout so bad, and your future relationship will be better.
Note: This plan works for pretty much all girls that start off interested in you. Save all the rebel stuff for girls that aren't interested right away. This plan has never failed me, and won't fail you. Go get it.