Mmmmh. It's kind of a 7/10, but I just don't buy the premise.
If these were healthy, fertile women, men who wooed them would have a lot of children, who would end up changing the population's preferences just through evolution.
One resolution is that if women typically die at 45, then at 30 they are already worn out with failing organs and missing teeth, and the manga simply doesn't depict this.
The other is that recently people invented healthcare and the trends still haven't caught up with the fact that life expectancy went up to 70. (But it would have been so easy to just say that...)
What exaggerates this problem is that IMO the manga artist is not great at drawing MILFs, which, um, way to not appeal to your core target group, dude.
Can't really tell how big of an issue that is, because it's not my fetish, but they look perfectly young to me. Like, I can tell they're not highschoolers, but they look maybe 25?
Those issues aside, though, I can't say it's not a novel plot, and it does some interesting things, so it's not a bad read. A bit too many sex scenes, maybe; feels like it can't decide if it's porn or a serious fantasy story.
But overall OK.
BTW, what's up with the MC's name? So far I've only seen girl characters named "Ceres", which is usually short for "Celestia" or the like.
