Just like every other time for the past nearly four years, I swung open the door to the men’s bathroom and ushered her inside, stopping only when I saw her look up and say, “I’m a big girl now, daddy, I want to use the girl’s bathroom.”We were on the fifth floor of the San Francicsco Museum of Modern Art, just the two of us in a small hallway. I’m not sure you can call this “going by herself” considering I opened the door to the women’s room, eye-scanned it and said “Hello? Hello?” like some bathroom-duty secret service officer and then stood guard by the door, all while taking pictures and posting them online for the entire world to see. But still. I heard her do everything by herself, and when she appeared beaming at the door, I could tell she was super proud. Big girl indeed. I can’t believe there will be a time in my life when this won’t seem like such a big deal.