you're so young don't beat yourself up about it. its absurd that they expect you to know what you wanna do at 17. don't rush into something you're not certain about. heck even take a gap yah or two.
to give you a starting point; do you want to make money and have a career? if yes, study something like a degree apprenticeship, medicine, nursing, allied health, dentistry, engineering, comp sci or accounting. you'll have no problems making $$ straight out of uni. if yes but don't wanna go to uni, consider the trades, apprenticeships, starting a business or joining the army. if no, study whatever interests you.