I don't want to visit my grandmother
Why not? Why aren't you going to visit her?
I am angry at her.
You shouldn't ignore your grandma regardless of how frustrated you are with her. It is important to spend time with family.
I'm pissed at her. Don't wanna go.
You are allowed to be angry at your family, but I believe that it shouldn't be for long. Your elders should be respected, and do you think your grandma really knows why you're mad at her? How about talking to her on how you feel first so both of you can understand each other.