When I was 4 I believed that My birthday was like any other holliday, meaning that I believed everyone celebrated it. I had a birthday party, and when guests arrived, and they wished me "Happy Birthday", I would say "Happy Birthday to you too!"
A childhood belief about birthdays

others believed things like this
- 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 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
- I used to think my birthday was a holiday everybody celebrated ]w]— Rin
- I used to think my birthday was a national holiday and the whole world celebrated it— アノン