Your parents should speak with a local attorney or legal service.
A power of attorney just formally indicates that your parents give permission to somebody else to make decisions on your behalf. It's most commonly used for things like educational decisions and medical decisions. However, no place is obligated to accept it, and some places have specific forms and paperwork of their own they want completed instead. For example, a school district in Arizona may or may not recognize the power of attorney for you to attend school there. It's up to them. Some doctors or hospitals may not want to recognize it. None of them have to.
Anyway, you'd need to speak with a local attorney or legal service. Annnnd, you're probably going to need to confirm with relevant schools, doctors, etc., that the power of attorney you're obtaining is something they'll accept. Even if they accept a power of attorney, they may want specific wording or clauses for their purposes.
one of ojs ex lawyers started a free legal advice site. shapiro or something like that.
and heres one for free legal advice on questions