A "juvenile" is a person who has not attained his eighteenth birthday, and "juvenile delinquency" is the violation of a law of the United States committed by a person prior to his eighteenth birthday which would have been a crime if committed by an adult. A person over eighteen but under twenty-one years of age is also accorded juvenile treatment if the act of juvenile delinquency occurred prior to his eighteenth birthday. See 18 U.S.C. § 5031.
[cited in JM 9-8.230]