>>14 seems very biased against relationships, so I wouldn't take his advice to heart.
So it's a RL relationship huh? I would say what you should do first is try to get her out just with you, or with some friends if that's all you can get. If you already know eachother well, ask her if she wants to go to the movies or something. I personally don't see a problem with confessing and saying you like her. It really depends on the type of people you are, I guess. All the girls I've liked didn't find it strange that I told them I liked them, and told me they liked me too. If you're nerdy type of people, chances are she won't expect you to be really cool and smooth about getting with her.
BUT I'm sure you can get into a relationship with her without confessing, too. Ask her out sometime. If you've never done it before though, it can be nerve-racking. BUT if you're not a really outgoing person, you should definitely get to know her before you ask her out. Get to a comfortable level so your date won't be full of that dreaded awkward silence.
tl;dr get comfortable with eachother before you make your move.