AITAH for wanting to prioritize my education over my friends?

I am a college student with a pretty decent GPA. I wanted to prioritize my college studies and not get behind, because I didnt take studying seriously in high school and it negatively affected me and almost led to me not graduating.

I have this one friend. She wants to hang out. I’m like “sorry I can’t this week, I have midterms coming up next week and I need to study”.

She starts calling me selfish and saying that I am a bad friend. She’s even saying she doesn’t want to be my friend anymore because I never “spend time with” her.

So I’m just wondering if I’m an AH here and if I really am being a toxic friend.