I wish I didn't have an autistic mother
Why say that? What's wrong with your autistic mother?
I am sick of her and I do not want to live with her anymore
You are being selfish to not want to help your autistic mother. You should cherish the time that you have with your family and nurture the relationships with your parents because they will not be here forever.
She's too overbearing sometimes, I need to get away.
Your mom sounds like she can be a hassle, but she is worth the effort and time. Try to exercise some patience with her and let her know that you love her, but need a break every now and then.