If it's math facts, I think that's developmental. Around 7 is the earliest I see kids memorize math facts. My dd took an interest at that age. My ds the dysgraphic also started to be able to memorize math facts at 7, though he didn't have him mastered til about 11 due to his LD. I'm sure there is variability, but at least here, it was a developmental thing.
Variability: I just checked my notes and DS was still 5 when he got Timez Attack-obsessed and cemented all his tables. That's one kid, but fwiw, schools here routinely have kids memorising their addition facts from 4. I don't say it's wise, and I certainly don't say that a kid who isn't ready then necessarily has a problem, but it clearly isn't impractical as a general expectation or it wouldn't be one.
