Moving in w my bf

I am 19, almost 20 and in college. I do not like living with my aunt, and my bf's looking for a place. We want to move in together because we love each other very much. Despite the fact we have been dating for 4 months now, this is unlike anything I've ever experienced. My mom was super strict in HS to the point where it traumatized me and I'm terrified to tell her I'm moving out ( not mentioning my bf for a reason). I'm scared she won't let me move out or will go crazy line always. I'm also scared to tell my aunt. Even tho I'm an adult I'm so scared. How should I approach this. Does anyone have any advice?