I broke my sisters glasses when I was 8
Why would you do something as awful as breaking your sister's glasses?
She made me mad by being stubborn
It's wrong to damage someone's property, and even worse to physically assault them, even if they annoy you.  Your sister didn't mean to make you so mad, and she didn't deserve to be treated that way.
You're right but it's alright, she didn't care about it.
If she wears glasses she might not be able to see well without them. Because of your anger she had to deal with her limited vision until her glasses were replaced. I hope you at least tried to help her get by during that time she was without her glasses.