What do I do?!?!?!?

Alright, well theres this girl in one of my classes. I've had her in classes in the past, and we're friends, jsut not like real close or anything. I've liked her, but never really done anything about it. Yes, I know I mentoined another girl, but you'll see in just a moment. Anyway, shes the exact type of girl I want to date. She's into cars, she likes racing, she works on her cars, she has a motorcycle, shes smart, shes extremely beautiful, shes a cheerleader, she plays softball, shes extremely beautiful again, and shes very hard headed (I find that attractive, I have no idea why). The thing is, I'm not the most handsome guy by a long shot. I'm pretty athletic, I play sports and all that stuff, I just don't have a great body. I'm built like a defensive lineman for a football team, if that helps you get the picture. Unlike me, she always gets pretty much any guy she wants, whereas I've never even had a girlfriend (yeah, sad, I know). So, shes pretty much out of my league. Well, not pretty much, totally out of my league. We sit next to each other in one class, and we talk and flirt a little, but I don't know if it can go any further than that. We've got our big homecoming dance coming up in a couple of weeks, probably late September or early October, and I'd like to ask her to that (if she doesn't already have a boyfriend, I dunno about that), but I just don't have the confidence to ask out a girl like that. I really don't know what my question is, but I just need any advice you can give me. The last time I attempted to ask a girl out, it was practically the same situation, and I failed miserably that time. The reason I've never done anything, and pretty much ignored my feelings for her is because she's so far out of my league, its really not even funny, so I've kept myself occupied with other girls. But part of me hopes theres a chance there that she'll say yes, but then the rest of me thinks she'll say yes out of pity.