Houou Gakuen Misoragumi

From Aerandria Scans:

Kei is a girl who's only interested in other girls! However, tricked by her mother, she enrolled in an all boys school, thinking that she'd be able to make her high school debut at a co-ed school. To normal girls, being surrounded with hot guys at an all boys school might be heaven, but to Kei, this is hell! What is Kei to do at this place without any other girls, where she has to try her best to keep her real identity a secret?!