Our last child has come of age. With our guidance, and without it, she learned to walk and to read, to cook and sew and ride a bike and drive a car. Singing seemed to be divinely granted. There were piano lessons and Girl Scouts and summer camp and basketball league. She was an easy learner and an eager one. She spurned my attempts to guide her sartorial style, developing her own at 18 months when she insisted on dressing herself—many times a day.

When it came time at age three to swim with the big kids, she was told she could not go in the deep end unless she could swim the length of the pool at our summer bungalow—60 feet. Hearing that, she promptly barreled in and swam the length and back. So there!

She was an oppositional child from the get-go. But she seemed always to love the structure and purpose of school. With other parents—less distracted and more goal-oriented—she might have been a high achiever academically. With the luck of the draw being us, she still managed to yield a good scholarship at a fine college and make honors.

At home it was useless to ask her to help. When I pointed this out to her recently—her oppositional streak—she listened intently. “How best to oppose this characterization?” she seemed to wonder. I’m still waiting for the answer. I remember using it to her advantage early, when she wanted piano lessons like her big brother. “Not until you are six,” we told her. We never had to tell her to practice after that.

Life with her has been full of conundrum. It started with a 36-hour labor that yielded a docile pink girl-child who took regular naps and weaned herself easily at 10 months. Later, the intensity of her emotional fits would have us consider a consultation with a neurologist. (Note to parents; eliminate nitrates first.) When her father asked her at age two and a half to explain a recent nuclear-powered outburst, she explained “Oh, Daddy, sometimes I’m a fussy girl and sometimes I’m a happy girl.” It has been my mantra ever since.

This week, we will hear her sing at Carnegie Hall with a Skidmore College choir and celebrate her birthday in the city. By age 21, most of the barriers to adulthood have been breached. For American kids, it means you are legal to purchase alcohol. For a family whose living depends on people drinking it, we would find it hard to be tee-totalers ourselves. But our family is full of people whose lives have been destroyed by the very substance that sustains us. When our daughter comes home for her birthday this weekend, she’ll celebrate at home with good champagne and at her father’s bar with tap beer. With what she has taught me, I know enough to trust her to do it all with care.