Here’s a quick timeline of when young men have been ordained to the priesthood over the years

Young Men general presidency: Aaronic Priesthood holders offer precious blessings through the sacrament. The First Presidency announced changes Dec. 14 to the timeline children and youth in The Church of Jesus Christ of Latter-day Saints will complete Primary, move from one class or quorum to the next and attend the temple for the first time. The changes, effective January 2019, also impact when young men may be ordained to priesthood offices.
Here’s a quick timeline of when young men have been ordained to the priesthood over the years

Young Men general presidency: Aaronic Priesthood holders offer precious blessings through the sacrament. The First Presidency announced changes Dec. 14 to the timeline children and youth in The Church of Jesus Christ of Latter-day Saints will complete Primary, move from one class or quorum to the next and attend the temple for the first time. The changes, effective January 2019, also impact when young men may be ordained to priesthood offices.
Changes announced Dec. 14 by the First Presidency will unify when children in The Church of Jesus Christ of Latter-day Saints move from the Primary program into youth programs and could result in earlier ordination for some boys to the priesthood.
Beginning in 2019, young men will be eligible to be ordained to a priesthood office in January of the year they turn 12, 14 and 16.
Ages for ordaining young men to priesthood offices are not “doctrinally mandated” and have varied throughout Church history, according to materials released by the Church. The following is a historical list of ages for priesthood ordination:
- Before 1877: No age specified; mostly adult men and some boys, ages 8 and up
- 1877: No age specified; mostly youth, ages 9–19
- 1908: Deacons: 12–14; Teachers: 15–17; Priests: 18–21
- 1934: Deacons: 12–14; Teachers: 15–16; Priests: 17–18
- 1954: Deacons: 12–13; Teachers: 14–15; Priests: 16–19
- 2012: Deacons: 12–13; Teachers: 14–15; Priests: 16–18