I used to always get nervous on the first day of school. Introducing yourself to people for the first time is always stressful because you don’t know if they’ll be nice or not. Something that helps me is taking deep breaths, I inhale and count to 4 then I exhale and count to 6. Do this for 5 or 10 minutes before you go to school and you’ll feel a lot better Hope this helps, good luck :)