My first daughter made me a father (with significant help from my wife). I felt unprepared then, and still do, on occasion, even though she is now 21. For example, I am still unprepared when she calls in a funk about tomorrow's final exam (in which she ended up doing more than fine, thank you).
Our son was born six and a half years after our first daughter, and our second daughter was born six and a half minutes after him. Ask me about twins another time, or boys; this time my assignment is daughters. My daughters have taught me about dance, and fashion, and the photosynthesis cycle, and scuba diving, and inductive geometry. They have taught me that observation is not judgment, that you don't have to be a feminist to support feminism, and, distressingly, that the world is cruel to women in ways that men only know when we worry about our daughters.