N.H. Rev. Stat. Ann. § 605:1

No minor under the age of 18 years, except with the consent of the minor's parent, nor any person supposed to be of unsound mind shall be permitted to plead guilty or shall be put upon trial until counsel has been appointed to advise him or her and conduct a defense. If such person is poor, witnesses may, on motion of his or her counsel, be summoned in the person's behalf at the expense of the county.