Does she like me or him? He's more in her league, but I don't know...?

She might like you and the other kid. She seems to be flirty with both of you. Maybe the other kid is her best friend and that's why they hangout alot. You should try talking to her and winning her over. Because since the guy is asking her to prom, he likes her. Just try talking to her more and get closer, and she'll prolly end up liking you *(;