I used to believe when adults grew up only 4' 9" or lower are still classified as kids.
A childhood belief about getting older

others believed things like this
- I used to think that I was smarter than adults. Now I know kids are smarter than adults in many ways— Marshall M
- I used to believe that school was a place kids go to get turned into adults.— Samantha
- I thought that kids' pee was yellow and adults' pee was clear.— Aretia
- I used to think that adults spoke an entirely different language (not English) when kids weren't around. — Swordfish
- I used to believe that toilet seats were for kids only and that adults sat directly on the bowl. — Evan Klyne
- I thought cartoons were for kids and "real-life programs" for adults.— Ichigo