Muriel Spark’s Loitering with Intent (1981) was published when she was 64.
The novel is written in the first person, framed as a memoir, as Fleur Talbot, the celebrated writer, looks back, “in the fullness of [her] years”, to the weeks and months of winter 1949-50, when she was working on her first novel, living in a bedsit, supporting herself by working in secretarial jobs.
It is an excellent book. With an excellent plot.
If you are a fan of literature over fiction, I recommend it. The themes are still important in 2018.
It was made into a film in 2014. It’s 33% on Rotten Tomatoes.