The Chilbury Ladies Choir by Jennifer Ryan

Chilbury is a story told through a series of letters, signs, and diaries set in England in the early days of World War II. Kitty is a young teenage girl in love with the older Henry (a fighter pilot) who is in love with Kitty's older sister Venetia, who is in love with the mysterious Mr. Slater. The best character of the story is the stalwart Mrs. Tilling, a widow and nurse whose only child, David, is going off to war as the story starts. She starts off kind of mousy and quiet, but gradually becomes a force to be reckoned with. And then there's the colorful Prim, who starts the (at the time unheard of) all women's choir, which brings together many of the women of the town when they need each other's friendship and support most.

When I first started reading it, I thought it was trying too hard to be another Guernsey Literary and Potato Peel Pie Society, which I loved, but I eventually got sucked into the story and wanted to know what would happen to Kitty, Venetia, and the formidable Mrs. Tilling.