Hourou Musuko

A little story description from pages:
ShÅ«ichi Nitori is a 5th grade student who likes to bake and has always been something of a feminine boy. When he transfers to a new school, ShÅ«ichi is mistaken for his 6th grade sister on his first day. Then he ends up sitting next to Yoshino Takatsuki, a tall, boyish girl who everyone calls “Takatsuki-kun.” They both have secrets they can’t let anyone know…

It is very nice story and I think you should try it.
Enjoy