[Fenimore knows this is true--she accepts it to be true on most days and usually follows it herself--but she doesn't feel like being rational now. Yet there isn't anything that she can argue against it, so instead she looks down, biting her lip, as her face turns red from suppressed emotion--mostly anger, but also a mixture of others she doesn't want to come to the surface.]
[action] this 500 year lifespan's sounding pretty good.