Really like this girl but not sure what to do here? Please give some advice.?

There is this girl who is 1 year older then me, shes honestly one of the kindest, funniest, best looking girls I know. WAY out of my league if you asked me, but for some reason she talks to me 24/7 texting, msn, skype, you name it, shes always talking to me. I never really thought of her as anymore then a friend until we hung out one night at a party, then my feelings changed and i'm crazy over her now. She always tells me about how i'm her best friend and whatnot and that's what really worries me that she doesn't like me as anything more then a friend. I'm not sure if I should tell her how i feel about her or not, i don't want to ruin our friendship and end up not talking anymore, but at the same time i feel so strongly about her i don't just want to sit around while some other guy gets her instead, because there are MANY other guys that I know are trying to get with her as well. Please be serious and thanks for the help.