Hello,
It is great that you are interested in plastic surgery at such a young age. That being said, many (including myself), would likely question how much you actually know about the specialty/like about it (unless you have a parent who is a plastic surgeon and/or someone close in the family).
If you want to shadow a plastic surgeon, you could email or call them. I do not see how much help you would be as a volunteer given the fact that you are only a high school student. Also, private practice plastic surgeons may not be as amenable to it, as they have a practice to run and it may not be good for the practice. Academic plastic surgeons may be more open to it but even then it is unlikely that they would be open to having a high school student volunteer or shadow. It is too early.
Most importantly, I would say the focus would be to getting into an excellent college (or you can apply to combined BA/MD or BS/MD programs, if you are sure you want to pursue medicine), and then focus on getting into medical school (and/or secondarily the best medical school you can get into, that will provide you with more opportunities). Then you can do research and shadowing as a medical student (you will be taken much more seriously then and be given more opportunities) and go from there. Also, keep in mind that plastic surgery is a highly competitive specialty (and it may remain that way by the time you enter medical school), so you will have to excel while in medical school as well. That is my advice.
Glad to see you are interested, good luck with everything. It's a long road, but it's fun. I'm a fourth year who applied to plastic surgery residency, so I'm not quite there yet, but fingers crossed.
