Sasami: Mahou Shoujo Club

In this world lives a group of people who call themselves "Majo" or "Magical Girls." They hide their powers so as to assimilate into society. They have been living together in harmony with humans for many years, as had their predecessors long before them. Sasami has had magical powers since her birth. However, at the age of three, she was told by her parents never to use her innate powers, and from then on, she kept them secret. On the first day of a new school term, newly transferred teacher Wajuu arrives, and from then on, Sasami's life begins to change tremendously.

(Source: ANN, edited)