What do you want to do as an adult?

No idea

Here's what high school boils down to: GPA. You need a good GPA so you can get into a college and get some scholarships so you don't end up to your eyeballs in debt. As far as figuring out what you want to do, you just gotta go try stuff. Experiment with hobbies and other activities, go intern places, volunteer, get your feet wet. If youre into the outdoors I can recommend some stuff. Once you know what you want, you gotta set a goal, figure out how to get there, make a plan, then execute that plan.