How to tell my mom that me and my daughter are moving out with my boyfriend ?!

She’s going to freak out because he’s not the father of my child but I feel like it’s none of her business ? She doesn’t know anything about him because she’s judgemental. She goes to church every Sunday but because he’s half black shes reeeeealllly not gonna like that. I’m turning 22 years old. I have a job and I go to school & he also has a kid he sees on the weekend. I know shes gonna have a fit about it. So I’m not sure how to go about this conversation without it turning into a huge deal. Any ideas ?

& yes me and him have been together for a while. I’ve known him for yeeeeears