Like the other posters said, look into taking classes at your local college. If your grades are good enough in HS, it won't be a problem.
Take something like econ 101 (not programming) or physics. Depending on the school you can take classes at, I think you'll find you'll be getting your a kicked by the information. What you used to find so easy in HS will now be much more difficult. You'll actually need to study :)