I was told that children of different ages were in different "grades" in school -- first grade was when you were six, fifth grade was when you were ten, etc.
However, my birthday is in February, which is in the middle of the school year. When I was in Kindergarten, I started getting increasingly worried right before my sixth birthday because I thought that after my kindergarten class held the usual in-class party for me, my teacher would pick me up, physically drop-kick me out the door to the classroom, and leave me to find my way to the first grade classroom by myself.
A childhood belief about teachers

others believed things like this
- A[n] nth grade teacher only had to finish the nth grade when he or she was in school.— MD Caruso
- I used to believe that the Chinese boy in my kindergarten class flew from China every day to get to class.— Debi
- I remember a girl in my kindergarten class told me she wanted to be a waterfall when she grew up.Anon
- I used to think my elementary school gym teacher's name was "Jim Class".— Brandon Campbell
- 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 people only grew, physically and in age, on their birthday. — Aretia