Catherine, Called Birdy (by Karen Cushman)

A historical young adult novel set in the 1200s, in which Catherine narrates her fourteenth year.  She's rebellious (insomuch as she can be in the 13th century) and resisting being married off by her father, while commenting on feudal life and the people around her. 

The diary format and general charm and self-possession of Catherine reminds me a bit of Cassandra and I Capture the Castle. The well-researched historical details makes this immersive and fascinating. It gave me a glimpse into medieval life that managed not to be too anachronistic in a portrayal of a  young woman and her social world. Great read!