Rick Beato has at least one child with absolute pitch, with stunning ability to name chords and the discrete notes in them. Here's the short video: https://m.youtube.com/watch?v=t3Cb1qwCUvI

I'm not a musician, but I'm told the kid's way of naming the chords is particularly adept from a musician's point of view, and that's because the dad (a very accomplished musician) helped teach the kid. I am sure Rick has made more videos about what he did.

The only age-sensitive part is the ability to map the chords to the colors.

Eventually, you would want to teach them to map the color to the chord name and recognize the root of the chord. But that can be learned any time.

Also keep in mind that if a kid learns all the colors, you'll want to continue practicing to "bridge" over the age where they would lose the ability to recognize perfect pitch. If they mastered this at age 4, they could still potentially lose the ability if they don't practice during that period.

Clearly, it makes sense to have perfect pitch only in connection with a particular instrument for practical purposes.

Besides being a neat party trick, it gives more possibilities and makes things easier if a person wants to work with music professionally, especially with academical (aka "classical") music.