"Year of his age"

1. Mosiah 6: 4
   4 And Mosiah began to reign in his father’s stead. *And he began to reign in the thirtieth year of his age, making in the whole, about four hundred and seventy-six years from the ^atime that Lehi left Jerusalem.
2. D&C 107: 45
   45 God called upon Cainan in the wilderness in the fortieth year of his age; and he met Adam in journeying to the place Shedolamak. He was eighty-seven years old when he received his ordination.
3. JS-H 1: 4
   4 His family consisting of eleven souls, namely, my father, Joseph Smith; my ^amother, Lucy Smith (whose name, previous to her marriage, was Mack, daughter of Solomon Mack); my brothers, ^bAlvin (who died November 19th, 1823, in the 26th year of his age), ^cHyrum, myself, ^dSamuel Harrison, William, Don Carlos; and my sisters, Sophronia, Catherine, and Lucy.