This is more of an event than a belief.
When my cousin(4 yrs.) was in church one day and going up to communion, there was someone who had glasses and hair like Harry Potter. So he said" Look Mom! It's harry potter!"
A childhood belief about films

others believed things like this
- i used to believe Harry Potter was real— charlotte
- I used to believe that Hitler's first name was Harry.— Paul
- My uncle harry has a very long beard and a hariy face. I used to think he was a wizard.Anon
- Oasis - Don't Look Back In Anger
"Oh, Harry can't mate
He knows it's too late
As he's stalking, oh my..."— Santa Puncher - I used to believe that people who wore glasses were blind and could only see when they had their glasses on. Anon
- I used to think that church songs were pop music. Well, we did sing them in church every week...— Roxy