I think that's true- I know Sarah has one that she may or may not have put away like mine, and I've heard of other writers too.

Maybe it was just me, but I could come up with ridiculously fantastical and complex stories as a child, and I remember enacting them with friends, or toys, or by myself. You sometimes hear children doing this, and their stories, while inventive and imaginative, are also meandering and self-satisfying. I don't think first-love-story-ideas are quite as bad as that, but they're certainly more like imagination explosions rather than the refined stories we've created since using our honed craft.