I know that 8 years of college are required to become a vet, but what are the first four years about?

I've been wanting to be a vet ever since I could remember (I'll add that in case anyone finds that relevant) and I've been blowing up google today because I am confused. So 8 years to become a vet: 4 years of ____ and 4 years of vet med school. What are the first four years of specifically? Can anyone tell me what the first 4 years require? I'm ending my sophomore year of highschool and my gpa is usually a 3.2-3.8. I plan on volunteering heavily at the vet clinics offered in Honolulu (My residence). I specifically want to know if I can go to Colorado State University straightaway. And if I can't because the first four years can't be completed at a vet med school can anyone recommend decent schools in CO? Thank you. You probably have no idea how much I'm freaking out at the moment.