u/Impressive-Hair2704

I’ve tried asking people and googling but to no avail. Hope you can help me :)

About 25 years ago, when I was 15, I was at a friend’s summerhouse and read one of her mom’s books so I might misremember some things.

From what I remember it’s about an old woman who works as a caretaker and maid for an even older one. The oldest woman dies after falling down the stairs and the caretaker is brought in for questioning as it is well known these women hate each other and the elderly lady being generally difficult/very particular about how she wants things. During the questioning, all told from first person of the caretaker, she more or less tells her entire life’s story including confessing to another unrelated murder.