Baby daddy’s evil mother

Advice please

I had my daughter 3 months ago and my baby daddy is in the Air Force and was not able to be there for her birth. His mom finally came around and saw the baby in the hospital and has even baby sat before. Even tho she had said some very hurt ful things I still forgave her and made it right so my daughter could have a relationship with her. Recently my baby daddy has the opportunity to go to Germany for 2-4 years and at first he was wanting to take us with him and figure it out we even talked about marriage but then he talked to his mom and she convinced him that we need to stay here because I need to go to college and she wants to be in her granddaughters life. I personally think she is wrong and it has pushed me further away from her.