Apparently it depends on whether you consider the series premiere as one episode or two; Wikipedia (which I used for reference) lists it as two separate episodes, providing a total s1 episode count of 20, vs imdb which lists it as one single episode, providing a total s1 episode count of 19. Memory Alpha lists the episode as s1e19, and I'm inclined to trust those nerds. At any rate I edited my comment to include the episode title for clarity.

Regardless, yeah, I think it's probably a turning point episode for a lot of folks, and it's the first of many war introspection episodes that help make the series timeless.