Now, with a view to what's coming, we remember that we were explicitly told that Abraham was 86 when Ishmael was born. So Ishmael is now 14.
Before the flood Scripture records that it was not impossible for men to conceive when they were much older than this: ‘And Jared lived an hundred sixty and two years, and he begat Enoch’ (Genesis 5:18), but in those days, for whatever reason, human lifespan was much greater, and after the flood the reduction in lifespan went hand in hand with a reduction in the age of fruitfulness.