Mrs. Salad was a Deanna Raybourn fan, she liked her "Veronica Speedwell" series a lot. And Pun Daughter had read this and recommended it, so I picked up the Kindle version.
I don't think she got to read it, unfortunately. And I don't know if she would have liked it. I finally got around to reading it, though, and I thought it was a decent page turner.
It's about a team of profressional assassins. And the gimmick is that they are four ladies (see title) "of a certain age", and that age is well past middle. They work for a shadowy organization called the "Museum", originally formed to hunt down and kill escaped Nazi war criminals, since expanded to other villains the law, for whatever reason, can't touch.
But it is a cliché of the assassin genre—there's even a TV Tropes page about it—that the organization you work for will eventually put out a contract on you. The ladies (Billie, Mary Jane, Natalie, Helen) are sent on a retirement cruise; they are enjoying themselves, but by sheerest lucky coincidence discover that they've been targeted. And escape by the skin of their dentures, but they are (of course) concerned, and somewhat peeved, that they've been marked for death.
The book is a weird combination of its absurd premise, lighthearted wisecracks, and explicit, sometimes gory, violence.
But it's a definite chick book. And it wouldn't be a chick book without irrelevant commentary about home decor. Example: they break into their victim's home via a bathroom; Billie, the narrator, observes the "vanity was a modern slab of concrete studded with tiny fossils". And there's a "flokati rug" on the floor. She disapproves. But things get better as they approach their target, sleeping in his "wide, low California king" bed, in a room which has the original parquet flooing: "After the modern atrocity of the bathroom, I'd been afraid he had remodeled the heart out of the old house."
And a few seconds later, there's blood all over the California king and the parquet, so… oh, well.