In the book Mr. Midshipman Hornblower, explain how Hornblower changed from the beginning to the end?

The novel is an abbreviated but typical coming of age story and presents Hornblower first as a confused and seasick adolescent without a dominant drive or even a defining character. By the end of the novel he is a commissioned lieutenant, trilingual, confident, and a leader of men. He has killed other men in combat, led combat squads on desperate missions, and made adaptive decisions contrary to established usages but appropriate in the instance. The novel begins with Hornblower as a timid seventeen-year-old and ends with him as a resolute and self-confident twenty-three-year-old.