I used to believe that people grew backwards, too. My older sister complimented me on a dress, for instance, and I told her I'd put it away for her for "when she was my age".
Maybe I had some early knowledge of reincarnation... or perhaps I just watched too much "Mork & Mindy".
A childhood belief about getting older

others believed things like this
- a friend of my little sister's had 4 older brothers, so she thought that when you got older you grew a penis!Anon
- My older sister had me convinced that noodles grew on trees, but that rice was man-made...— Trusting little brother
- I used to believe that Madonna's "dress you up in my love" was "dress you up in nylon."Anon
- I used to believe that my cat was a reincarnation of the buddha and was sent by satan to squash me.— Nazza
- My 6 years younger sister used to tell me that I was younger than her. She was just growing backwards.— Taryn
- My older sister told me squirrels were poisonous, and I believed her until I was 9.— Jenni