No passaport

My bfs mom hasnt seen my baby since she was born shes 4 months now n i was wondering if we go over there to where shes at in mexico do we need a passaport because its legit right at the border on the mexico side n i have my birth certificate n social just no Passaport n i dont wanna be gone for the holidays i wanna be here for my family so i wanna go this month. its in Tamaulipas