What should I do about this girl?

Okay, so there is this girl in my class who I "like". that's an understatement really. I'm in eighth grade and I have never felt like this about a girl before. We really get along and we are great friends, but I am really scared that she doesn't like me like that at all. I mean, I guess sometimes it's kinda like she likes me but most of the time, I feel like she just wants us to be friends. I don't know if I should just ask her out and see if i get lucky or not ruin our great friendship and say nothing, but then the problem with that is then I have these feelings for her just boiling inside me... Please help me.