Overall enjoyable. I liked that there were so many female characters, and although you could tell it was written by a man in how he described the women's internal thoughts, particularly on their own bodies and aging, it didn't cross the line into gratuitous or off-putting. I enjoyed Kate's characterization, but the mystery in the end had no clues for the audience to try to piece together. As a thriller, it seemed a bit rushed in the final act and descriptions of grief that felt really authentic in previous scenes were in my opinion too suddenly and jarringly revealed to be deceptions.

Minor Spoiler:
Why would the final victim think "you" when confronted by the killer given who the perpetrator turned out to be? Why would he be almost as excited to catch her in the shower as to kill her considering her thoughts just before the murder?
/Spoiler

My only other complaint was that the author took time to give Kate the internal narration that she had a lifelong nickname for her daughter and then never once used it. In that same paragraph as revealing it - the one time it was used - 'Melissa' is written 5 or 6 times!

Tl;dr - Pacing issues aside, I had a few sections of the reveal that I had trouble reconciling in hindsight. However, it was a good, quick read that was fairly authentic with it's female characters and didn't rely heavily on tropes, instead giving the POV character quite a bit of nuance. 3.5/5