Lately i've been developing a crush on one of my friends, and it's starting to bug me.

I have a few classes with her and we sit next/near each other most of the time. In these classes everytime we're sitting next to each other we flirt (not all the time but most of the time) and we both seem to enjoy it.
She seems to be flirty and playful with pretty much everyone though, so it's not like she only flirts with the people she likes.

She's also abit shallow. She comments on hot guys or something and it makes me feel abit low because i know and she knows that i'm not "hot" or attractive.

She seems to be friends with everyone at school, and me i'm not as popular (well i'm hardly popular, but i still have friends).

I'm not very interesting person to get to know because i don't really have a great life but she's easy to get to know and always interesting.

So all these points make me feel that she's way out of my league, which sucks.

She also has a boyfriend. He lives a few hours away from where we do, so she doesn't seem to see him much, but i still know she likes him very much.

I had the idea of going out with her one night, just the two of us. We'll have a few drinks and then i'll tell her how i feel (kind of weak yeah?). The rejection wont hurt as much this way and it's better than telling her at school or something when she could somehow hurt me even more, plus i wont be thinking about it all day.

I just need to ask her if she'd like to have a few drinks with me.

Advice? Thanks.