Help!!!🤷🏾‍♀️🙏🏾

So I’m moving across country to be with this guy. I been knowing I was in middle school, we been talking for about 15 years (I believe) and I’m 22 he’s 30. We been talking about me moving in with him since I graduated high school and college. The problem is I don’t know how to tell my family that I’m leaving to go start a new life with him. My mom and other family members isn’t really supportive of me like they are with my brothers. I really just want to say f it and go without telling them. I need help and advice