Follow your interests / passions. Don't pursue a career just because it pays really well. Pursue it because it interests you.
I once read that asking someone what they want to BE when they grow up is the wrong question to ask. A better question is, "what do you want to DO ...". Thinking about what you want to DO can open up a wider range of possibilities, as opposed to pigeon-holing yourself into a specific occupation. For example, "I want to be a doctor" vs "I want to help people stay well". A doctor is a doctor, but helping people stay well could take you down any number of paths - doctor, nurse, medical technician, researcher, immunologist, nutritionist, psychologist, etc.
If you're unsure of your interests / passions, then take a broad range of general interest courses in the arts and the sciences, and see what piques your curiosity. Take your time to decide. Some people never decide, some people stay in one career their entire life, and others make radical career changes during their lifetime. There's no rule - do what's right for you.
Above all else, I would suggest taking a course in financial literacy. I work with post-secondary students, and the one thing I see is how they struggle with being able to properly handle their finances, because they've never really had to up until now. Basic concepts like budgeting, saving, compounding interest, managing credit / debts, and investments will be invaluable to you throughout your life.
All the best!
Mark