Should I tell her? Or should I not?

Well, your best option is probably to let her find out, and if she asks you just say that you were hesitant to confess because you didn't want to hurt your friendship and that you didn't think she thought of you as more than a friend anyway. Basically if she mentions it to you then just say "yeah, I like you but if you don't feel the same I'd still like to be friends; I'll try to get over it".