Im 15 and going to be a teen dad please help?!?

Okay well my girlfriend just found out she's pregnant a week or so again and our parents are both supportive. I have a few questions though. Even though the mother and I are in a relationship, we don't live together obviously, so do I get the baby on weekends or something? And do I pay child support even though im not even old enough to have a job? Will the baby get my last name or hers? I am just really confused and would really appreciate advice. I will be apart of this childs life it is my baby and im still the dad no matter how old I am. Advice would be greatly appreciated. Thank you.