I have just found out about this, and I was wondering.
Here is my story (a short one):
Since I was 4-5, I didn't want to talk to anybody who was a stranger. In elementary school, I didn't have any friend and got extremely nervous if I had to present a project verbal. In middle school, it was worse. I was bullied every day, and if I wanted to tell a teacher, or my parents, I couldn't, because I was afraid. Now I am in high-school, and I still can't comunicate very well. I only have one best friend. If it comes to speak in front of the class, I feel like I am in hell, and I have a panic attack. At English classes I can't say a word (I am not native English speaker), even though I know the right answer almost all the time, at Math I don't want to go to the blackboard because I am afraid I will do something wrong, and everyone will laugh, etc. When I am at home, I barely speak, too. I don't know what it is. Do you think I have selective mutism? Please help.

I forgot to say that I speak only with 3 classmates.