I used to think that your 'golden birthday' was when you were as old as your parents. After a while it dawned on me that this would be physically impossible.
A childhood belief about birthdays

others believed things like this
- I used to believe that people only grew, physically and in age, on their birthday. — Aretia
- My parents have the same birthday -- month, day, and year. I though all mom's and dad's had the same birthday.— Cait
- I used to believe your parents PICK your birthday.— Stella
- My birthday was on a different day every year, assigned by my parentsAnon
- I used to think that your birthday changed every year, and that your parents just decided what day it was.— Daniel
- Up until I was almost 11, I thought that a birthday suit was a special outfit you wore only on your birthdayAnon