I just want to make sure of one thing. Does one of your parents, especially the custodial parent, live in New Hampshire? Your state residency is NOT determined by where you attend boarding school. UNH is not giving instate tuition to everyone who attends St. Paul’s, Exeter, etc. If you in fact attend boarding school in the state where your custodial parent resides, that’s fine. Just making sure.
Some states also consider children of non-custodial parents who reside in the state residents for purposes of tuition. I don’t know UNH’s policy. If your non-custodial parent lives in a different state it MAY give you another option for instate tuition.