i not american my self but i know that the "prom" is a big thing in america so if u ask her to the dance dont just go up and ask her. even if u just give her a few roses with a letter and bring it to her at her house. i have also heard of writing it in candles somewhere. i know for sure to do something romantic and i dont know wat she or u are like but roses and candles are always good for being romantic
best of wishes hope it all works out