Sounds like you're doing great so far! Other than #1 below, medical schools will not care about anything you did in high school. So now is a good time to set the foundation for strong grades and extracurriculars in college. A few things you can do:
1) Do as well as possible in your college classes. Even though you are technically a high school student, these classes will count towards your college GPA that medical schools will see regardless of where you end up going to school after you graduate. If you're struggling, seek help early and often!
2) If it's possible, see if you can get a CNA, EMT, or phlebotomy certification through your high school now (when it's free to you, I'm guessing? though you may need to be at least 16 years old). This will give you an avenue for some direct patient care experience and a paycheck. This only helps if you use the certs and actually work, so keep your certification current even if you don't work right away and find a job using it as soon as you can.
3) Get into the habit of volunteering regularly. Find something you enjoy, and something where ideally you're interacting directly with people who are different from you and/or disadvantaged in the healthcare system (in poverty, homeless, disabled, refugees, etc.).
4) Once you're in college, you'll want to think about opportunities for things like research and shadowing doctors. You don't need to do that yet, just keep it on the back burner.
Regarding what medical schools will think about going through school quickly - I have not heard of anybody being accepted without at least 3 years of college (after high school) under their belt. The youngest people in my class were 21 when they were accepted, but the vast majority of people have 4 years of college plus a gap year or two before starting medical school. So be prepared to either take a minor in something you're interested in, or take a light course load so you can really beef up your extracurriculars and spend lots of time studying for the MCAT.
Good luck!
