Should i just move out?

ok well im 17 and a senior in high school. i dated this girl last year and my parents found out we were having so they broke us up. well they thought so but i still snuck and saw her. but now they found out again and threatened to take my phone and computer and stuff away if were together. then we came to an agreement that i cant see her outside of school and if i get any bad grades or get in trouble at school their going to switch my school and make sure i dont see this girl until i graduate. well i want to see her out side of school and now its going to be almost impossible to do that because theyll be watching me more closely. i really dont want to move out but my girldfirneds mom said i could move with them. if i do does that mean my parents wont support me in anyway anymore? ugh i never thought id be one of those teens that move out early but i just want to be with her. so any advice?