Boyfriends Mother

My bf mother has always been the controlling type. She tries to.get.involved in every thing. Bf is really close to her but has been distancing himself because he is growing up. We've been together 4 years. Own a home together and have 3 animals together. We're really very established for 23 year olds. Good jobs and comfortable. We've decided to stop preventing pregnancy and we both really want it. His older sister who is a nurse and married does really well and just had a scare. She doesn't want kids yet but his mom.made a HUGE ordeal about it and was very negative and vocal to me about it. Makes me nervous for her reaction if we conceive. Anyone else dealt with this before??