Hi there @Garebear21!
Welcome to AT&T! We are pleased to see you have taken advantage of our Community Forums. I personally use my online account for all my billing needs as well. So I can completely understand your desire to get this account setup!
I am going to attach a link here which indicates the ways you are able to acquire your account number. As we have taken off your private information from the forums for your safety. Please click here for additional online account setup steps as well.
Let us know if you have any additional questions or concerns. Have an awesome day!
Shenoah, AT&T Community Specialist