Pregnant, and scared because ill still be living at home

I am 24 and havent told my mom im pregnant yet because ill still be living at home. Even though I have a job and can fully support myself and my baby, I know shes going to be extremely disappionted and tell me to go live with my boyfriend or something. I dont want to live with my boyfriend because there are too many people in his house as it is. I need to tell her as I am 14 weeks, but im terrified as to what her reaction will be. Advice please?