Ah! No matter what I answer, it really doesn’t matter since you don’t necessarily have to know what you want to do until college (or even halfway through that)!
Take your time figuring out what you want to do. Really. Not only does a lot of tuition go into your thoughts, but so does your whole bright future. Don’t start to limit it now!!
Go through high school and if you know you want to continue to higher education, go to university. In fact, if you can afford it, I highly recommend going to college, because you really learn a lot about the basics of various occupational fields there and it’s the best place to discover what you want to do in life. Take all the basic courses, explore the electives, and then I’m sure you’ll find your calling.
To answer your question though, I was about five when I started wanting to become a doctor. I had my own reasons—family deaths, personal medical history—but they weren’t really anything to distinguish me from almost any other person out there. Knowing I had to excel in school to become a doctor, I followed “the doctor’s path” and earned straight A’s and tried to be well-rounded by joining many clubs and sports. Then in high school, I had this mindset that I was already in “the doctor’s path” so even if I wasn’t really sure why I wanted to become a doctor anymore—outside of the fact that I still did want to help people (though there are many ways to do so) and that it seemed to make my family proud—I continued with what I was doing.
However, it was in college that I officially decided I wanted to become a doctor. I mean, I’ve always been good in the sciences, but being good in biology or chemistry is so basic that you only get a hint of what medicine is like. It was when I started taking the upper division courses, especially neuroscience, when…omg, my jaw hit the floor. It was SO. FASCINATING. I couldn’t get enough of learning about the mysteries of the brain. But you know, with medicine, once you’re involved in one subject, you can’t really help but go into other subjects. I mean, to fully understand neurochemistry, one had to go into biochemistry, and from there physiology and anatomy, or in any order actually, since everything is interconnected. It’s like an infinite web of knowledge that traps you once you show any true interest. I knew I had to have more and the paths that opened themselves to me were research and becoming a doctor (or both). So I volunteered in both activities: at the hospital and in a lab. No offense to the lab people, but I personally think I’m more a doctor person.
So all in all, while I was already on “the doctor’s path” with a major in Psychobiology (because it fulfilled all the med school prerequisites), it wasn’t really until my junior year that I knew for sure that I wanted to become a doctor more than anything else.
I hope I didn’t bore anyone with that long story and that someone out there actually finds it helpful. :-) Good luck, anon!