I have to say,
I've taught my 7 y/o DS to knit and he is really good. His tension is only a wee bit wonky, and that is because he is afraid to slide the stitches up in case they fall off, so he pulls on the stitch a fair amount.
But he won't really knit often. I just have a nice child sized pair of needles with about 25 stitches across on it and some Red Heart (it puts up with his pulling).
Anyhow... he's done about 3 inches in 3 months.
He'll watch me and grab it and knit for a row (say about 10 mins worth) and then put it away.
And I am thrilled with that :D
But it took me a lot of patience to teach them that far
My DD is 5, and she can say the rhyme and knows the idea. She will hold the left needle, and wrap the yarn, but I have to do the rest.
And I am thrilled with that too :D
But it took a lot of patience
And the ability to say, "no more, walk away or Mommy will have to go and lock herself in the bathroom for a few minutes again!"