When I was young and folks or animals passed away at very old age my mother would say they "died of old age". I remember believing this was an actual cause of death, like there wasn't some disease or ailment caused by age that did it, but that an old thing literally just died with no traceable reason aside from the fact that they were old, as if there was no exact explanation and at a certain age all the organs just collectively shut down at once and the person just died. I believed this until I was 17 and can even remember the conversation that led to my realization that I was wrong.
"Great grandma passed on a month ago", I said.
"Oh no! What caused it?" The lady asked.
"Old age"
"Right but how did she die?"
"She died of old age"
My mother then pulled me aside to explain that just being old doesn't kill people, it's other real problems that come with it. I was so frustrated with my own cluelessness
A childhood belief about people

others believed things like this
- When I was little I believed when an actor died in a movie, he died in real life.— Ben
- I thought there was some video games so hard that if you died on them you also died in real life!— Kakuri
- I used to believe that when we died (and animals) died they were picked up in a bus with there name on it.— Lawny
- When I asked my mother how Elvis died, she told me that he ate too much candy. — Katie B
- I used to believe that you died when you turned 100, the exact second.— Tianne
- When the Queen Mother died when I was quite upset because I thought royalty did not die.— Carrie