I used to think 8 was old. When my oldest was still a toddler, a friend of mine was hired to homeschool some elementary aged children, and I asked her when they started making brachos. "Eight," she said. Eight! That's so old! Surely three year olds are all trained to make brachos and keep Shabbos.
Elazar is now 9. I've moved the goal post. He is still very inconsistent about wearing a kippah and point blank refuses tzitzis except on the rare occasion that he takes a class with Jews. I know that it's a minhag, and he still has difficulty keeping Shabbos, and how can I get hung up on a minhag when he's still struggling with d'oraisas. He tells me 10. We'll see what happens when he gets to 10.
I know that I've always said that he's three years behind. I don't mean "behind" insofar as any negative connotation whatsoever; I love homeschooling because it gives those children who need three years of wiggle room plenty of wiggle room. There are no age-(in)appropriate expectations and we can work with his capabilities. So I guess I will see at 11 if he is capable of things I would have assumed for an 8 year old. And if not, we will work with his abilities as they present.
Removing all academic expectations and having very broad end goals (will be able to read as an adult, will be emotionally capable of making a living as an adult, will have loving and functional relationships as an adult, will care about Torah and be equipped to keep mitzvos as an adult) is the difference between a miserable, stressed out, anxiety-ridden childhood (for both the child and the parents), versus having a child who wakes up every day thrilled to enjoy his day and explore the world.
Is it a mistake to set aside academic expectations for him? Will he grow up incapable? Sure, I worry. But the other possibility seems more painful and equally doubtful of producing results.