They Grow Up Fast

But Why?

“‘Enjoy your youth,’
Sounds like a threat.”
-Regina Spektor, Older and Taller

It’s a truism spoken by many parents of older kids: they grow up fast. When this is said to a parent of younger kids, it is meant as a caution to enjoy it while it lasts, even though the earlier years can be a challenge.

Worth mentioning are the two Greek words that are often invoked in discussions of time: kronos and kairos, countable time and the subjective passage of time. Pro tip: use these terms in regular conversation to sound impressive, and if anyone asks, tell them that you’re a Substack savant!

Why is this sentiment so popular?

If you press your elder-parent-friend for answers, they will likely say something in the vein of kairos. “Hey man, it just seems that way.” This is fine, but beyond our mere perceptions I think there’s a kronos/numerical logic to this as well.

As an example, take a typical situation where a family has three kids, each of them born three years apart.

In the graph above, notice two things: the eight years where the average age of all kids is five or under (green), and the eleven years needed for the youngest child to reach age five (peach).

Any age could be singled-out, but I choose age five because that’s when children are more independent and go to school for full days.

A parent’s perception that their kids are young and have been young forever is valid. The needs of the youngest child are often the limiting factor in activities. The time from when the first kid is born to when the last kid is no longer a little kid is eleven years, and it’s still eight years if you’re going by average age.

Each new kid lowers the average age. Once the final kid is born, the average age increases one year per year, which makes things seem faster than before. Once the youngest kid is five years old, more possibilities open up.

In the area highlighted yellow, this is probably what most people think of when they imagine parenting. No old kids, no young kids, just regular-aged sitcom kids. This lasts for 3/22 years in this example, and then after that when the oldest kid is 15 attention is turned to the issues of a budding adult.

I also think there is a meme-like quality in the way this idea is transmitted from parent to parent. All new parents are tired, all parents of school-aged kids worry, and all parents of teenagers notice how quickly they arrived at this point. We just say things to each other and these cliches get repeated with varying resonance and degrees of actual meaning.

With the world population exceeding eight billion, parenting, though meaningful, is not an original activity. The next time you hear, “they grow up fast,” let that wizened parent enjoy their cliche. They’re probably super tired and couldn’t come up with something more clever to say.