What if the student is never "ready" though? As part of a project for a small Christian liberal arts college, I had access to anonymized data on admissions and class schedules. They accepted a great deal of homeschooled students. Can you guess what how many of them placed in remedial math classes?
Many times more than their traditionally educated counterparts. The school was not big, these catch-up classes were full of kids home schooled by well meaning parents who never thought their kids were "ready" for basic mathematics. This is a colossal failure, when you get to college without knowing basic math, entire departments are simply closed to you.
Interestingly, they often placed in line with their peers in language, with many placing highly in foreign languages as well. Maybe that says something about the priorities of the average parent of a homeschooler?
https://www.psychologytoday.com/blog/freedom-learn/201003/wh...
Math, math seems more like a side effect of our big old brains. Math can be learned, but it fades quickly. We are able to do it, but we aren't really built to do it.
Anyway, i guess i'm arguing language is hard to screw up.
It's a huge disservice to lump these students in with the others. The students that can actually do the work get held back (and I'm not talking about the high-level students, (who are usually brutally retarded in their development, unless they take matters into their own hands), this impacts the mediocre students as well).
It might make a big difference to the individual kid. One of my earliest memories is seeing how adults read words and numbers, I must have been between 4 and 5 years old. I asked my parents to show me how to do that and they replied "no, you'll learn this when you're older, this is not for you." Later in first grade, learning to read and write was no fun at all (I blame the teacher), and guess what: a good number of kids could already do it. Where would the harm have been in taking a few hours to teach me that stuff a couple of years earlier, when I first wanted to?
This anecdote is about learning things early, but overall I agree with you that learning stuff gets massively easier at a later age. I never really understood math and physics until I was in my twenties and had the opportunity to explore the subjects on my own terms.