Medicine interests me for some reason.
Well jeez, leave some room for life. Having a rigid frame of what you're going to do with your entire life going into highschool isn't exactly productive.
If you want to go into medicine, great. Trend towards that but keep an open mind. Also, I know you'll probably end up giving up once you realize that the boundless energy and enthusiasm of a 13 year old rarely lasts longer than a week, but please do not beat yourself up if you feel like quitting. I wouldn't even advise you to start learning Latin in the interest of entering medicine in nine years. Do you think anyone in college or when you enter residency or even become a doctor would give a rat's ass that you probably half assedly learned Latin when you were 13?
Let's be realistic. You are probably a very average child and I suppose it's great that you have spunk but I really don't think it's the best way to spend your time.
So there's my two cents, whatever that's worth.