Owmyhead, the thing is, most of us here are adults. We do remember the angst and tragedy of our first crushes, but we see them in hindsight now for what they really were: no big deals. I know it seems like it's the most important thing in the world to you right now, but it really isn't.
You like this girl, right? You want to know if she likes you back. There is no way of knowing whether she likes you back if not by asking her directly. You should ask her out on a date (something as small as ice cream and an afternoon movie will work), if she says yes go out with her, take her hand, put your arm around her shoulders during the movie, kiss her even. You have nothing to lose, so just go for it.