The crystal ribbon / Celeste Lim.

Enhanced descriptions from Syndetics:

In the village of Huanan, in medieval China, the deity that rules is the Great Huli Jing. Though twelve-year-old Li Jing's name is a different character entirely from the Huli Jing, the sound is close enough to provide constant teasing-but maybe is also a source of greater destiny and power. Jing's life isn't easy. Her father is a poor tea farmer, and her family has come to the conclusion that in order for everyone to survive, Jing must be sacrificed for the common good. She is sold as a bride to the Koh family, where she will be the wife and nursemaid to their three-year-old son, Ju'nan. It's not fair, and Jing feels this bitterly, especially when she is treated poorly by the Koh's, and sold yet again into a worse situation that leads Jing to believe her only option is to run away, and find home again. With the help of a spider who weaves Jing a means to escape, and a nightingale who helps her find her way, Jing embarks on a quest back to Huanan--and to herself.