Young men will be members of priesthood quorums throughout their lives. To help young men better prepare for the greater responsibilities of the Melchizedek Priesthood, Aaronic Priesthood quorums should be patterned after the Melchizedek Priesthood quorums. All young men, whether or not they have been baptized or ordained, should be invited to attend all Church meetings, including priesthood meetings, and be listed on Aaronic Priesthood quorum rolls as follows:
Deacons, 12- and 13-year-olds; Teachers, 14- and 15-year-olds; Priests: 16-, 17- and 18-year-olds, except those who have been ordained elders.This procedure keeps the records of each young man in the quorum of his age peers. . . .
Aaronic Priesthood Leadership Handbook, p. 2