Taking the Next Step, but I Feel Frozen in Place

I am starting on the next step in my life today. I was accepted into the Vet Tech program at my college. It's competitive to get in, and I still feel like there must've been a mistake or it's a joke that I got accepted. I don't feel good enough to be in this program, and every time I try to take a step forward my anxiety sky-rockets. I freeze, my stomach feels like it's full of rocks, and my mind starts spiraling.

I am afraid to tell my family, they'll only get angry and tell me to stop being ridiculous rather than try to support me... I want to do well in this program, but it's hard when everything in your mind is telling you that you can't do it. That you'll fail. That everyone hates you and doesn't want you in the program with them. That they think you're stupid and are tired of trying to teach you. It's horrible.

I want to be more confident, and I want to have more faith in myself. Do you guys have any suggestions for what I can do to help push past this? Please, I don't have many places to go to, but I've wanted to be a vet tech all my life. I don't want my anxiety to get in the way and ruin it for me.