Other 16 y/o here, this is very recognisable for me , a lot of people just dont know what its like, for the same reason people keep saying "why do you stutter" like it is some kind of choice, what helps most is to start doing any activity you like with a group of people (joining a sport club, maybe apply as a volunteer for the school paper, join a local discord server of a game you like). I got very lucky a few years ago with getting the friends i have today. At primary school i used to be in exactly the same situation as you and it felt horrible. I hope it'll get better for you.