My sister is 22 today. She is a mother. She is hilarious. She is brave. I love my sister more than I can say. My relationship with her has been unique and difficult and completely rewarding. Growing up, we were very different (and in a lot of ways that hasn't changed). When I wanted to talk things out, she'd rather say what she meant and leave it at that. I liked to have tons of people over, she preferred more intimate gatherings. I guess you could also say she does what she wants, and I do what's expected of me--it's been something I've always envied about her. We used to fight like crazy, as most young sisters do; arguing about clothes, the loudness of my music, about who had more popcorn... As we got older, and each of us scrambled through adolescence, we became more sympathetic to one another as young women. There was a dramatic shift in our relationship a few years back, though it's hazy and can't be confined at a definitive moment. Our relations...