Twilight Trial: Science Fiction

It was the summer of her 16th twilight, and she was nervous. She remembered the last three twilights, but they had not concerned her yet, for she had been younger and not required to go out into the twilight, to live or die, to breed, perhaps, to find something of value and bring it back or to start a new settlement (though nobody had succeeded in doing that for the last 60 twilights). She dreamed of finding a ruined city filled with knowledge and wonders, looming over a deep network of caves that would be enough to allow a new settlement. She dreamed herself the founding mother of that settlement. And then she looked at her own mother's worried face and remembered the death of her three older siblings, and she feared.

Inspiration: Thinking a bit about aliens, since I'm writing "Alien/Whore/Mother" on the bus.
Story Potential: High.
Notes: Ooo! Fun alien-perspective stuff, post-apocalyptic survival stuff--this could be a lot of fun to write. Like some classic SF.