Hello mcv081,
You impress me, so I have joined up to say so, and to add my bit to this discussion if I may...
Please don't lose sight of the fact that if you want to really make a difference in this world in a profound way, you CAN start right now, just maybe not in the way that is immediately apparent to you.
Maybe you could start with some kind of effort in the line of charity, I've heard of many young people who have started projects and funds, to purchase water wells for villages in Africa, for example. Do some research in this vein, see what others in your age group are doing, you are
not alone. See what sparks your interest and creativity, start making connections and plan and build your project with the support of that community (if there is no such community yet, maybe your initial calling could be to build a network for these youth to support each other?)
You could also try to earn a bit of money after school, or take a holiday job (that won't interfere with your schoolwork) and use that money to get involved in the micro-loan effort. That changes lives for people all over the world, and would give you the opportunity to see, very clearly, the results of your efforts for each person that you help. The loans people make on http://www.kiva.org/ for example, go from just $25 up to $400 dollars. (fyi, you'd probably need to enlist an adult to 'assist' you though, the website will probably require it, just to keep it legal
)
These are just a couple of ideas, you'll need to get creative and find a way that works for you, but it can be done. Even as a freshman, you can apply yourself in your free time, and really make an impact. I understand that this movie is inspiring, but
if your goal is to be free to make a difference and surround yourself with like-minded people, more than anything else, you need to get the BEST education that you can -- the more educated you are, the more of a impact you'll be able to make in this world. Christopher McCandless got a great education, and despite his troubles, waited until he was graduated from college to take his adventure. I went to college at 16, after being accepted in my sophomore year at high school, so I was just a little bit older than you. I wasn't rich or brilliant, but I was motivated. A lot of things are possible, even at your age, if you can become adept at balancing your amazing passion with patience and hard work, and incorporate the thoughtful guidance of people who have walked the trails before you.
I wish you great success in all your endeavors!