I'm one of the board members of the VIN Foundation and am happy to talk to you about becoming a veterinarian. I also decided to become a veterinarian in high school, graduated from Auburn University College of Veterinary Medicine and practiced several years in Florida. I then returned to Auburn and completed a residency in neurology and currently teach neurology and neurosurgery at the University of Tennessee veterinary school.
Since you are a junior in high school I would suggest two things. First, focus on doing well in school, in particular learning how to study. That way you will be prepared for college classes so you can make good grades. One of the biggest factors in getting accepted to veterinary school is your academic performance in college courses. You want to have good grades from the start of college. A common mistake I see is people make poor grades their first year or two in college. Then they decide they want to go to veterinary school and start studying harder to make better grades. The problem is at that point it can be difficult to increase your grade point average enough to get accepted.
The second thing I would recommend is to work for a veterinarian, even if you have to volunteer part time. For example, in high school I worked part time for a veterinarian cleaning cages and walking dogs. This is important for two reasons. Most important is to find out if you really want to work in veterinary medicine. A lot of people love working with animals but find they don't really enjoy some of the other aspects of veterinary medicine. You may find you love it. But if not, it's better to find out early on before you invest a lot of time, effort and money only to then find out you don't like this career.
Also, some sort of experience in veterinary medicine is one of the things we look for when deciding which students get accepted into veterinary school.
I hope this is helpful and please feel free to contact me with any questions or if there is anything I can do to help.
VIN Foundation Board Member