Yes you can legally "divorce" your parents. The legal term for the process is called emancipation. The laws surrounding emancipation vary by state and the minimum age to apply for emancipation is typically 18 years old, but may be a bit higher depending on what state you live in. The first step is to contact an attorney.
Yes, if a minor is living with an abusive parent or the parent(s) seem to be unfit to raise the child, the child can legally emancipate to be freed from the control of the parents.
You can petition a judge for emancipation. You must be at least 14, have no objection from parent, ability to support self, prove emancipation would be benifical for you.
