I’m in secondary school which is the same as high school and what I found is that I just shouldn’t shy away from talking to classmates or anyone else and it’s really helped my confidence. Sure I’ll stutter when I talk to them but they never laugh or mock me cause I’m friends with pretty much all my classmates and they know that I stutter so I just don’t care and talk to them. Hope you can get the help and advise you need. Good luck