I'm planning on becoming a veterinarian (i'm 15 years old) and.........?

i luv animals i have 2 dogs a gsd and a terrrier mix, i know its gonna be really tough 2 get into a veterinary school cuz there r only around 25 veterinary schools in the U.S and so i want 2 get into one of those schools after highschool, but i want 2 know what would the requirements be, what subjects do i have 2 excel in, etc...