There are prophecies that are fulfilled in the NT concerning Jesus 'coming of age'. This refers to Jesus becoming aware of, and fully embracing the knowledge of who he was.
Son of God
By age 12 he knew he was the Son of God, but may not have know the implications.
God
After his baptism he cleansed the temple, knowing that he was God.
Messiah
Though Jesus knew he was Messiah since the wedding at Cana, there are indications that making the choice to include gentiles in salvation came later. He did not fully embrace the cross until Gethsemane.