Not all 40-59 year olds have kids in high school or older.
I’m a “senior mom” – 48 with a 6yo and 8yo. And while I’m one of the older moms at Curie – I have plenty of company of moms and dads in their early to mid 40’s with kids in 1st grade.
I have quite a few friends in Scripps Ranch. Several are in the same boat as me – older moms with young kids.
You can’t determine the age of the child based strictly on assumptions that parents reproduce only in their late 20’s early 30’s… too many exceptions to that rule. Even more so when the parents are highly educated with strong careers.