Girl troubles

So there's this girl in my welding class. She is super awesome and i really like her. Shes one of two girls in that class and 28 other guys. Of all the guys in there she chose to come up and talk to me the entire class. I think she really likes me and i really want to ask her out. There's a couple problems though...Number one she has two brothers who are seniors that i play football with. Two i don't want to rush into asking her out and have her turn me down. But i'm afraid if i wait to long i will miss my chance what should i do?