I need some big life decision advice from anyone that wants to read!!

This all might be confusing, but I need some advice for a bit step I’m about to to take. My boyfriend and I have been together for about 6 months now, and he recently bought a house for us to live in and I’m planning on moving in with him on April 22nd. Im 18 and I currently still live at home with my parents. I’m technically kinda on house arrest right now by them, because I got in some trouble over New Years and they sold my car and took my phone. They cut off (what they thought) was all contact from my boyfriend, but I have been keeping in contact with him on an old phone since New Years. The plan is still for be to move in with him when he closes on the house....but they have no idea yet. I told my dad last night my plans and he didn’t take it well. My boyfriend is offering to drive to my house and pack me up and move me in with him in two weeks. Also buy me a car and I can go to school where he lives. My plan in to sit down with my mom this weekend and tell her the truth and tell her I’m moving out and about me keeping in contact with my boyfriend this whole time. Which I’m scared she may end up kicking me out as soon as I tell her. I don’t want to ruin my relationship with my parents, but this is something I feel in my heart I want to do. My question for everyone is, how would you approach this subject with my mom? Should I just come out and tell her everything? Have my boyfriend contact her? Should I not mention I have a second phone? I just need advice!