Nymph Haru's Cinderella Story

From MangaHelpers:

Haru is the star at her high school for young ladies of good family, and she is determined that she is meant to be a princess. She tries very hard to fill her idealization of what a princess should be like, but her instincts are sometimes thrown off by her family's history of being very poor. Spending her days with her younger brother Ataru and her friends at her school, Haru does her best to behave as the princess that she knows she truly is! [tethysdust]