Princess of the mansion

I am Yuki the only daughter of a traditional japanese family. I have 2 younger brother who are twins which is Kyou and Ren who is very protective of me. Our parents died when the twins was only 2 and when I was 6. I had to take care of them since then since I am the oldest I am the head of the house of Takashima. Our family has butler but I didn't know they were ninjas that protect my family. So I go to a school where a regular human and ninjas go to school together but it different section.