“I live in Pennsylvania and have a custody order for my child. The child will turn 18 in September of the beginning of her senior year in high school. Will the custody order remain in effect until she graduates high school or will it terminate once she turns 18 although still in high school?”
Typically, the terms of the custody order will continue until the student finishes high school. Consult your agreement, and if it is ambiguous on this point, consult an attorney who practices family law in your jurisdiction to help clarify its requirements.