As wedge said above, you're a very long way from having to pick a specialty and no one knows what Medicine and healthcare will look like when I start practicing, much less over a decade from now. But I can give you some advice for were you're at now, assuming you're in the US.
I decided I wanted to be a doctor in 9th grade. Probably not for the right reasons. If you want to be a doctor for the prestige, the respect of for the money, then you've likely got a limited and immature perspective. That's ok! I was in the same boat, but I made certain to do my research and get involved in healthcare volunteering later on. Now, I know that I'm going into Medicine for the right reasons. If you can, try to get involved in a clinical setting sometime in high school to dip your toe into the water. It would be good to start college with a little experience and a better idea of what you'd like to do.
Don't build your life around being a doctor. You've got a lot of potential and opportunity to do a lot of things and explore many careers. Diversify your interests and keep an open mind. Have fun in high school. There's a reason a bunch of classic rock songs talked about the teen years. Make them memorable!
You certainly don't need to pick a specialty right now. I wanted to be a neurosurgeon when I was your age (typical premed sort of thing to think). Now, after shadowing a few surgeons, I don't think that surgery is something I want to do. You have a lot (a lot, a lot) to learn and accomplish before you can realistically even start thinking about specialties. I suggest you take courses that suit and challenge your interests, both in high school and later in college. Focus on your talents and hobbies while identifying and addressing your weaknesses. You should try to enter college as a well-rounded person.
Hope that helps. If you have any questions, feel free to ask. I was right where you are not too long ago.
