I’ve been in a similar situation with on of my female friends back in the day. Here’s what I learned:
There’s a reason why you are friends for a long time and never become a couple. Sometimes, in the bond and comfort you have as friends, you forget what those reasons are, then you end up making out. A few things can happen then.
1. It gets weird, impacts your friendship.
2. One of you develops stronger feelings for the other, which the other doesn’t share, but wants to maintains the status quo (this also, eventually ends the friendship)
3. You both realize you’re great together, and live happily ever after.
I have very rarely heard of #3 happening. #2 is far more common. Tread carefully. I think that a mature conversation is in order where you explain to her, with no drama, how the recent actions have changed your feelings, and that you need time to deal with them if she doesn’t return them. In my experience, this is the price of fooling around with friends, unfortunately.