Donut-----Between the two options:
Girl #1 - Sounds too easy. Her readiness is a boost to your ego, but do you reeeaallly want to go to prom with her?
Girl #2 - Tough cookie, but someone worth your effort. You are all graduating and you are all going your separate ways. You've got a crush on her so now is the time to take a leap. It's now or never, no regrets right? If she says no, it'll be dissapointing, but at least you tried asking. If she says yes, you'll be finishing school on a high!