I am not from a native English speaking country. While in 5th or 6th grade, I learnt the poem -" Jack and Jill". I used to belive that both Jack and Jill were boys. I realized that Jill is a girl's name when I was a senior in university.
A childhood belief about names

others believed things like this
- Since the girls name Jackie is short for Jacqueline, I thought the boys name Jack was short for JackalAnon
- I used to belive that Jack Frost was a real man! and that he came and painted frost on the windows at night.— Tom
- Because of Pocahontas, I grew up believing Native Americans noises sounded like English to Native Americans.Anon
- "She's got the Jack" by ACDC was "She's got the Clap".— Cybela
- I thought Jack was a nickname for Jackery ( like Zack and Zachary).— Bootlebat
- I used to believe that tornadoes were spinning jack-o-lanterns in the air bent on destroying my house.Anon