What steps should I take now (as a Senior) to go into Vet-School?

A good start would be to reach out to local veterinarians and animal shelters. See if you can shadow or do an internship. If neither of these are an option, you could always volunteer your time. I know most non-profits welcome additional help in feeding, walking, and cleaning up kennels.

Before applying to Vet school for your DVM (doctorate in veterinary medicine), you'll first have to get a Bachelor's degree. While you're a senior in high school and while getting your Bachelor's degree, you'll want to intern/volunteer at a vet clinic. In addition to that you should consider doing volunteer work/internships at animal shelters and a maybe even a zoo. Or if your police station has a mounted patrol they might have an internship you can do, working with their horses. Basically anything in the animal field will help you out but I think it's particularly important to intern at a vet clinic so that you can make sure that's really what you want to do with your life. You're looking at 8-10 years in college and $240,000+ in cost (without scholarships).

On your application for Vet school they'll be looking for your internships and volunteer work in the animal science field.

I thought I wanted to be a vet until I did a 1 year internship in high school at a vet clinic. I found it boring and depressing. I'm now a zoo keeper working outside with different species of animals (wolves, bears, primates, etc.) and I love it! However, zoo keepers don't make near the amount of money as Vets so it's more of a career of passion.