Back when he was a baby and toddler and preschoolers, I thought all the milestone books were written for the very, very lowest performing child since he was years ahead by the time he was two. I thought the ages listed on toys, especially games and legos were disregarded by everyone because they were so off.
Funny you mentioning that, I remember thinking variants of the same thought like - it must be a marketing ploy and they put those ridiculous ages on everything to make everyone think their kids are advanced LOL
I had no idea of what to expect with DD - I was never tested and neither was DW - in fact I actually believed all of the 'anti-Bell Curve / Jay Gould' pseudo science that insisted that IQ testing is a sham. We only tested as a recommended means of trying to understand why our happy and outgoing DD was encountering peer rejection.