一个外国朋友想找一本英文书

一个外国朋友想找一本英文书 finding a fiction book i've read about a girl goes to see her brother during the summer and acting on stage with other people,then she has a relationship with a girl.she find out that her brother is a guy also.if someone have read this book,give me the title and authors name.i remember that first the girl sees the house the actors actress are living,it looks old.i don't remember any names in the book so it is very hard to find it out.