Unless you really feel like it might move forward, I'd personally, hold out on telling her. I've went through this a million and one times, and have regretted opening myself up like that on more than one occasion. Feel the situation out a little more before you drop any "truths" on her. If she starts to reciprocate the feelings, then most definitely tell her, until then, I'd wait..
Darius - I can't agree with you more about reading people. I can read just about anyone, like an open book, within the first couple minutes of just talking to them. I've called stuff on people from the get go, and had other people say "no they seem nice, bla bla" a month or two later, I can't even count how many times I've heard "you were right..", it's a knack I think a lot of us have grown accustomed to. It's always been a defense mechanism for me.