(This one is really odd, you have to know, this was after watching the movie the 13th year 5 times) I thought that I would turn into a mermaid on my 13th birthday and seeing as I am 14, my inner child is still depressed about it.
A childhood belief about birthdays

others believed things like this
- i used to think that the four years of college were also known as the 13th, 14th, 15th, and 16th grades.— lydia
- When I was a kid, I use to believe, when I put salt in my bath water I will turn into a mermaid.— marletha
- My parents have the same birthday -- month, day, and year. I though all mom's and dad's had the same birthday.— Cait
- i thought I got one year older when my family sang the birthday song.— I am the ghost
- I thought sadism involved being sad and depressed. Obvious, I think.— ]_]
- My birthday was on a different day every year, assigned by my parentsAnon