Wives and Daughters by Elizabeth Gaskell

Seventeen-year-old Molly Gibson worships her widowed father. But when he decides to remarry, Molly’s life is thrown off course by the arrival of her vain, shallow, and selfish stepmother. There is some solace in the shape of her new stepsister Cynthia, who is beautiful, sophisticated, and irresistible to every man she meets. Soon the girls become close, and Molly finds herself cajoled into becoming a go-between in Cynthia’s love affairs. But in doing so, Molly risks ruining her reputation in the gossiping village of Hollingford – and jeopardizing everything with the man she is secretly in love with.