Girl I went to prom with ghosted me out of the blue

I have been friends with this girl for about a year, not very close friends, but still friends and I decided I would ask her to prom. She said yes and we were excited and we went to prom and we slow danced and had a good time. After the prom she said she wanted to hang out more and I agreed, but about a week later she stopped responding to my snapchats and she wouldn’t even pay attention to me in the classes I have with her. I’m a pretty shy guy so I’m not usually the one starting the conversations so I am just a little confused. She used to hysterically laugh at any joke I would make and now it doesn’t seem like she even bats an eye. I don’t get what I did wrong and need an expert opinion on what happened.