Or you could always ask her friends. Most likely, she'd be somewhat guarded, when it comes to revealing her feelings to you, and more often than not (though it is rare), she'll be somewhat taken aback by your sudden expression of affection. If you have the guts, then you should ask her somewhere private - like walking her home or after studying together or summat - so she knows that 1) it's important to you, and 2) neither of you can cause a public disturbance.
Or if not, ask her friends. Even if you don't hang around them, if they recognize you, then they know something is up. If she's guarded, there is still at least one or two people she trusts with her feelings (her girl mates), and those one or two are the persons to ask. One could consider this option rather cowardly, but I think it's a rather easy step to take. One, you're not talking to her, so butterflies won't necessarily start up. Two, at least you'll find out where you stand; if they're trustworthy and know you're being forthright and sincere, then they'll have the decency to tell you the truth (instead of being bitches). Three, if you haven't ingratiated yourself to her friends, that's the chance to do so, and one knows that a good way to a girl's heart is through her friends.
But whatever. Like many personalities, no matter how much advice one gives to another, that other will still do whatever they want.
"I like refried beans. That's why I want to try fried beans, because maybe they're just as good, and we're just wasting time." - Mitch Hedberg (1968-2005)
"Football is about if you want to run and fight for each other, if you really want to play that killer ball." - Robin van Persie, Arsenal FC