It presents as rambling and effortless and naive, but, of course, you can only achieve that effect through art and experience. Picasso said he'd spent a lifetime learning to paint like a child, and Macaulay might have said she'd spent a lifetime learning to write like an artless young woman. It's an extraordinarily vivacious book to have been written by a person in their seventies.
It is also terribly sad. To be funny and sad at the same time- in the same voice- is something only the very best writers can do.