I want nothing to do with a girl I got pregnant.
Why do you feel that way about her?
Because I don't want my family to find out, and I also don't want to have to be a parent.
Whether or not you want to be a father, you need to take responsibility for your child. You need to be there to help raise your son if the mother wants you to be. Think about how the child would feel growing up without knowing their father.
Do I have to?
It's the right thing to do. If the girl wants you in her life, then you should be there to support her through the pregnancy and to help raise the baby. She and the child will be grateful to have you in their life.