I am embarrassed

I’m 15 years old and I’ve never done anything before. I met up with this boy, that I’ve been talking to for a while, and I had my first kiss with him. I was completely buzzing for the entire night. The next day he was acting kinda off with me but I ignored it. Later on he asked me to “sext” him and I straight away said no. I felt pressured to do it and I HATE that feeling. He could tell I was annoyed and so got annoyed with me. He’s now stopped talking to me completely and gone pretty much “whatever I don’t care”. What I hate most about this is that it was my FIRST kiss like ever. This was supposed to be really special and now I just feel embarrassed, angry, confused and I wonder whether it’s all my fault. He says that it was “a joke” but that’s not to me. Was this my fault? Was I acting too protective? Or is it the right thing to leave him and forget about him?