Boys were never 16 years old - they went straight from 15 to 17. Girls made up for this by missing out on being 19 years old.
A childhood belief about getting older

others believed things like this
- I thought that the difference between girls and boys was that girls have teeth.
Anon - I used to believe that little boys grew up to be girls and little girls grew up to be boys. — Darin
- In first grade a boy told me that he could see girls naked with his microscope lens. I beleived it for years.— Jeanette
- when I was a kid, I used to believe that only girls could be my friends and all other boys were my brothers.
— rajat - I used to believe that tigers were girls and lions were boys— Ruth
- I used to believe that all cats were girls and all dogs were boys.— jordan