Something similiar happened to me years ago; I never told her how I felt. Years later I said to her “do you remember that night I dropped you off at your moms house? I wanted to come in with you so bad”; She said “why did’nt you say anything!?”
It’s scary to try and advance on someone who is your freind. I would try to find some way to express yourself without being to heavy about it. Keep it light so she is not put on the spot. If you do it without putting her off the worst that could happen is staying where you are now.