16s was the hardest part of my stuttering life. Your brain is not fully developed and you dont know yet how to deal with all this shit. I would tell my 16 years old "me": \- Write an email to you teacher about your problem, they will keep it for themselfs and make sure nobody laughs and also that you could also talk less during the class. \- If they still laugh, start going to the gym, get big and then they should stop laughing. Now I am 30 and the last time somebody laughed was many years ago. I work with smart adults, maybe thats the reason.