Ishmael a teenager who became a baby?

According to the Bible, Ishmael was 17 to 18 years old when he was sent to the desert with his mother Hagar. Miraculously as soon as he went to the desert he became a "BABY"?

How does a 17 to 18 years old teenager become a baby? How do we know Ishmael was a baby, because the Hebrew texts specifically uses the word "Naar נַ֫עַר" the same word used to describe Moses as being a baby.

When she opened it, she saw the child, and behold, the baby (NAAR נַ֫עַר) was crying. She took pity on him and said, “This is one of the Hebrews’ children.”(Exodus 2:6)

The same is used when referring to Ishmael. Notice how the angel of God said, “God has heard the (NAAR נַ֫עַר) boy crying”

God heard the boy crying, and the angel of God called to Hagar from heaven and said to her, "What is the matter, Hagar? Do not be afraid; God has heard the boy crying as he lies there.

How can a 17 to 18-year-old teenager be cast under a bush crying?  “And the water was spent in the bottle, and she cast the child under one of the shrubs (Genesis 21:15).

The question is if Ismael was a baby, which he was according to the Hebrew text, then this means Isaac was not born when they were expelled to the desert? We know from the Bible Abraham was 86 years old when Ishmael was born (Genesis 16:16). We also know Abraham was 100 years old when Isaac was born (Genesis 21:5). Here we have a gap of 14 years between Ishmael and Isaac, we also know Ishmael and his mother were expelled when Isaac was being weaned (Genesis 21:8) this usually is between 3 to 5 years. This would make Ishmael at least 17 to 18 minimum, without using a 5-year weaning term.  How then could a 18 year old teenager become a baby?

We call this textual corruption. This shows Ishmael was the chosen Son to be sacrificed as a test.