When I was in kindergarten I remember hearing that when you were six you'd go to 'the big school' for first grade. I was baffled when we sang 'Happy Birthday' to someone on her sixth birthday and no group of 'big kids' came to escort her to 'the big school.' I eventually figured out that this was a generality.
A childhood belief about classes

others believed things like this
- I thought you didn't have to go to school when it was your birthday.— M_1
- Up until I was almost 11, I thought that a birthday suit was a special outfit you wore only on your birthdayAnon
- I used to think that a birthday suit was a special outfit you wear on your birthday— Bri
- i thought I got one year older when my family sang the birthday song.— I am the ghost
- I used to believe that on your birthday, you didn't advance to your next age until you ate your birthday cake.— Casi
- My parents have the same birthday -- month, day, and year. I though all mom's and dad's had the same birthday.— Cait