Well I was thinking...
Something like this happened to me when I was 14.
She was my best friend since we were 6 years old. She started dating this guy that she had just met. He turned out to be really cool. The 3 of us were all good friends. Then, my parents went to Germany and left me and my step brother at home to go to school on our own (yeah right), and fend for ourselves.
Well, I invited him over. He pressured me into losing my virginity. One of the biggest mistakes I've ever made.
It didn't take very long for my best friend to find out.
Of course, she hated me. She called me wh***, promiscuous person, all of that. It basically caused me to lose the majority of my friends.
We started talking again 4 years later. We had both graduated high school by this time and people forgive/forget. We talked about the whole situation, and of course I told her I was very sorry and nothing of the sort would EVER happen again. To this day, we are still best friends. We work together and both of us have kids that play together.
Things will work themselves out over time. Either she will befriend you again, or she'll never talk to you again. Either way, you need to move on and give her some space.