I'd agree that military is a good way to go but it's not like they take everybody who wants it. I've always felt it was pretty hard to get into.
Learn as much as you can as early as you can. Read books. Get a job at the airport pumping gas. Get a job and save money for your PPL at 17. Stay out of trouble. Plan on going to college (where and what your major is doesn't matter).
Check out this site, as it has a lot of info for a newbie.
www.jetcareers.com
Also see this link to see how I did it.
http://www.jetcareers.com/content/view/65/132/