My younger brother, David, is the most important person in the world to me. He was diagnosed with Autism when he was about 3, and when he was I subconciously decided I had to set a perfect example, help be his teacher, and help him navigate the world. When I was younger, I would often take him aside to explain certain social customs, prompt him to go ask the other kids to play, and do anything I could think of to try to help him when he got stuck, and I continue to do my best to help him. The need to be a good example and teacher to younger siblings is a feeling common among many eldest daughters