I like the premise and the theme of this piece. The fact that a sub-500 word story has a strong theme and a moral to it is not easy to do, and I liked the ambitious way you tried to fit so much into a story of this length.

The time travel aspect felt kind of dropped in (there wasn't a lot of lead in and then the time traveler was gone as soon as she appeared). I think this is a situation where a story this ambitious almost needs more time and space to play things out, or else to be streamlined a bit to really trim it down to its baer bones in the few hundred words that you have to work with.

Overall, I love how ambitious this story was and think you have a really strong foundation for something that can be expanded and further developed.