Women, what is the skimpiest you have dressed around your brothers?

I share an apartment with my younger sister and she loves to dress skimpy. When she goes out she dresses fine but as soon as she come home she puts on tiny short shorts and even smaller tops. Not that i really notice but she never wears a bra and you can clearly see her through her top. Also her shorts are really short to wear when she is sitting you can see her panties through her leg openings. Recently in the morning she has even been eating breakfast in nothing but a tank top and panties. I try not to look but she is a good looking girl who plays vollyball and soccer and is in really good shape. My question is for the ladies, is it normal for women to dress so skimpy in front of their brothers? and if so, would you be mad if you noticed your brother sneaking a peek? she has caught my eyes wandering and all she did was laugh at me and say "enjoying the view"? What should i do?