My Life Crisis

My grandpa has just died because of an heart attack. His last dying wish was for me, the first heir of the Lane family to go to a school he personally picked. His condition was for me to try to find a wife. Another condition was for me to pretend to be a boy instead because he told me to do so. So with that he enrolled me in a private rich high school to live as a boy without telling me beforehand. To top it off my little sister will be there to help me pull it off as a boy without being found out.