Garudapurana 1.94.22

1.94.22

grahaṇāntikamityeke keśāntaścaiva ṣoḍaśe /
āṣoḍaśā'dvāviṃśāccācaturviṃśācca vatsarāt //

or until its mastery, according to some; and the tonsure of hair takes place in the sixteenth year. / Up to the sixteenth, twenty-second, and twenty-fourth year,