How old was Ishmael?

How old was Ishmael when he was abandoned by Abraham?
He was an infant.	He was a young man.
Genesis 21:14 Abraham ... took bread, and a bottle of water, and gave it unto Hagar, putting it on her shoulder, and the child, and sent her away. Genesis 21:15 And the water was spent in the bottle, and she cast the child under one of the shrubs. Genesis 21:18 Arise, lift up the lad, and hold him in thine hand.	Genesis 17:25 And Ishmael his son was thirteen years old, when he was circumcised in the flesh of his foreskin. Genesis 21:5, 8 And Abraham was a hundred years old, when his son Isaac was born.... And the child [Isaac] grew, and was weaned.