Hi AceKat! I'm a junior in highschool, so it wasn't too long ago that I was in your shoes!
Okay, so freshman year really is like middle school. You're just at at different school. Basically just treat it like any other year. Don't get too stressed, and most importantly don't slack off. The work is pretty easy, but there is a lot of it so it can get pretty overwhelming. If you have decent teachers, don't be afraid to befriend them! They will help you a lot the next four years!
This is the time to discover yourself- what makes you uniquely you! Experiment! Find things you like! Be social!
High school is what you make it, so don't worry too much darling!. You'll do great. Feel free to message me!