I was also convinced that everyone's sex automatically changed every few years, kinda like Hutts in Star Wars or Gethenians in the Hainish Cycle (neither of which I was aware of at the time btw, so I didn't get the idea from either of those places ). But that's no sillier than the things cis people take for granted about sex and gender well into adulthood, so meh

I also had a really distorted sense of distance. I thought the shops 2 streets away from where we lived were the next town over XD