Without any prompting from stories or movies, I believed faeries, elves, and many other such creatures were real from a very young age... faeries were generally small and had wings, but elves were beautiful people, roughly human-sized with long pointy ears, usually had no wings, liked to sing to the stars at night, and sometimes gatheried into great shining elven armies and made war on bad creatures or people who really pissed them off. Maybe I was accidentally channelling JRR Tolkien or something. :D That was all before I read my big bro's Dungeons & Dragons set, too. Imagine my surprise some years later when I read Lord of the Rings...
A childhood belief about fairies

others believed things like this
- I thought buffalo wings were wings from a buffalo, for years I looked for their wingsAnon
- I believed that lightning bugs were faeries....
::sigh:: I miss those enchanted years of my youth.— Andrea Sorenson - I used to believe that if you ate enough chicken wings, you'd sprout wings and be able to fly.Anon
- I convinced my sister that chocolate milk was made out of Keebler cookie elves, she believed me for a month— Rainbow Steel
- I used to believe that unicorns were real creatures. I thought they were just another type of horse.Anon
- I used to beleive that the computer bugs were real creatures that lived in your pc and ate away at it.— BoBo