Hey !
First of all, happy birthday !! 🎉

When I was about to turn 18, I was also scared, because it feels like a big step when, you said it, it doesn't change much all of a sudden. It's more of a gradual thing, like yes you technically "become" an adult, but mentally you don't change immediately.

I'm sure you'll be fine. Just do your best !! And never stop doing what you like.
If you ever want to talk, remember you have my Discord ✌️