For some reason my parents used to celebrate my "half birthday" (I was an only child). Since my birthday is September 17 then my "half b-day" is March 17, St. Patrick's Day. As a child I didn't understand that everyone's half birthday fell exactly 6 months from their actual birthday. I thought St. Patrick's Day was EVERYBODY'S half birthday and that was why we celebrated it!
A childhood belief about birthdays

others believed things like this
- When I was a teenager, I used to believe that someone's name-day occured as half-birthday.— Marcas
- 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 that on your birthday, you didn't advance to your next age until you ate your birthday cake.— Casi
- 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 think that if i didn't celebrate my birthday each year my younger sister would catch up with me— q