I don't want to hang out with my family when my girlfriend visits.
Why is it not important for you to see your family?
I hate my family, they treat me like shit
It is important to have good relations with your family. They are the people that will always be there for you.
I don't care, it's my life.
You should explain the situation to your girlfriend she might be confused why you are both avoiding them. Being open and honest is a great foundation for a relationship.