Who could sign me up for school?

My mother is letting move away with my friend. I’m going to be seventeen early March. My Mom lives in Oregon and I will be in San Jose. She doesn’t want my Dad to sign me into school because he doesn’t have coustody. Could my Mother write a written note and my friend’s Mom and I could sign myself up for school or what should I do? I really don’t want to do this a court way because I’m leaving tomorrow afternoon..