moving out ?

so my bf and I want to move out maybe a month or 2 months after we graduate high school were both 18 and want to start our own lives together. He personally wants to move out because he has many family issues at home and I wanna move out with him because I know lving alone can lead to depression and also because I want to start a life with him and my parents can be controlling too . I'm ready to move out and were ready to start our little family soon the only problem is I know my mom will be very disappointed, how do I fight that and not feel guilty ? /: