She wrote it when she was 91 and 92, and it was published in 2020. I got to thinking about this reading Jan Morris’ recent book of published daily reflections, Thinking Again. Not necessarily peak quality or peak beauty - peak likeliness to concern themselves with big questions about things like sex, death, meaning, their place in the universe, and so on.
I have a theory about writers, which is they reach peak expansiveness around age 50 or so.