Yo, I'm 19 and when I was around your age I had the same issues. Unfortunately one thing you have to understand is that people are gong to laugh. That's what sucks about school and being around kids that don't understand. It's just something your going to have to get adjusted to it. Sometimes it actually is funny but sometimes it's not. One thing I would say trying to do is smile through it or make jokes about it yourself. When I was in school people would laugh at me for stutter and I would get mad and embarrassed but I learned how to smile and laugh it off even if I didn't want to or wasn't felling it. It's just what you have to do in school. It also has helps to find a good group of friends that don't care about your stutter or a group of friends that mildly joke with you about your stutter. The more comfortable you get with your friends with your stutter the bettter you feel about it sometimes. I know it sucks but it's the hand we were dealt.