Tuck Everlasting by Natalie Babbitt
At dawn, Mae Tuck set out on her horse for the wood at the edge of the village of Treegap. She was going there, as she did once every ten years, to meet her two sons, Miles and Jesse, and she was feeling at ease. At noon time, Winnie Foster, whose family owned the Treegap wood, lost her patience at last and decided to think about running away.