On the first day of school, my daughter Pickle saddled up her pink Barbie bicycle, adjusted the straps of her mermaid helmet and then we were off, the two of us biking to begin first grade.

My son Hardy had left about 15 minutes earlier, tying his lunch box to his backpack with a green piece of twine, and biking to fifth grade. He is an old pro at navigating the streets and he asked his parental escort to stop following him years ago.

We all met up again briefly at the school. Hardy acknowledged my vigorous wave with a slight nod of his head, his universe now a group of 10-year-old boys. I still remember the first time, about halfway through the third grade, when I reached for his hand as we walked into school and he pulled it away from me.

Pickle and I continued walking to her classroom, holding hands the whole way. She had told me the night before that she was both nervous and excited. I told her that seemed about the perfect way to feel about a new adventure.

The hallways were filled with teachers, students and parents, too, most of whom I have known since Hardy started kindergarten. Some parents were smiling, some trying to hide their tears, and as we talked, updating each other on our summers and getting into the back-to-school routines, we also shared our sadness, right there next to the pencil sharpeners and jars of paste, that our little ones were growing up so quickly. Later, after morning meeting had finished and I shuffled out of the school, now holding the hand of my wife, Cathlin, I looked around at all the parents in the schoolyard.

Before you become a parent you have no idea this first day of school scene exists, most likely all over the world; some adults running to their cars screaming free at last, free at last, while others mill about the parking lot as if unsure of what to do next.

It reminded me of something my dad said to me just before Hardy was born.

“You have no idea what is about to hit you.”

At the time I didn’t like his comment. It seemed to have a bit of comeuppance to it, a “now you’ll see how hard it is” type of deal. But after Hardy was born I realized my father’s comment was the most accurate of any piece of advice I had been given. The enormity of parenting, both the highs and the lows, cannot really be explained nor prepared for.

When Cathlin gave birth to our children I was with her in the delivery room both times. For Hardy there were complications at the end of the delivery and Cathlin was immediately moved to another room more equipped to handle emergencies. Almost as an afterthought, the nurse turned to me as she left the room and said, “Here you go, Dad,” and handed my newborn son to me. Everyone had left the room, and I stood there holding Hardy stiffly and thinking that soon someone would come back and tell me what to do.

Eventually I realized I was on my own and found a rocker in the corner and sat down. I felt so incredibly alone. But I also felt content as I wept over my child for the first time. Even from a young age, the only thing I have ever really known for sure was that I wanted to be a father.

But it wasn’t the hospital scene that the first day of school most closely resembled. Rather, the sight of the other parents, many of whose children are younger than mine, reminded me that I have now been a parent for a full decade. This role defines my every waking minute, and if I ever forget this, my children are sure to remind me, usually in the deep dark of night when they cry out from their beds that they are scared or thirsty or can’t find their favorite stuffed animal.

The schoolyard scene of parents also took me back to a time so many years ago when I was just starting out as a parent, and although Cathlin was with me every step of the way, I felt completely adrift.

For the first five years of Hardy’s life I was a stay-at-home dad and it was an uneasy fit for me. We were living in New York city at the time and now instead of going to work each day, I wandered the streets pushing my son on Herculean stroller walks until my Achilles finally gave out. We switched to loitering in cafes and over many cappuccinos and sippy cups of warmed-up breast milk, I taught Hardy baby sign language until we could converse like a couple of third base coaches. I also took him to wrestling matches and women’s swim meets at Columbia University, located just a few blocks away from our apartment. And at night, after Hardy and Cathlin fell asleep, I watched episodes of The Wire, feeling as if the characters in the show were my only friends.

It never occurred to me, because my son was not even a toddler yet, to go to the playground. But then one day I wandered by and was amazed to see so many parents and kids there, my entire new subculture on display. I was both excited and nervous standing on the perimeter of the park feeling like a freshman quaking at the sight of the high school lunchroom.

I noticed a few other stay-at-home dads, but I didn’t want to approach them as I figured any other dude doing this job must be a total loser. The irony wasn’t lost on me, but still, anyone looking out on a playground knows that the moms are the stars of the show — they are the major leaguers, the Oscar winners, the cool kids who not only know how to take care of their babies but had also gestated and birthed them, and could feed them with their own bodies, too. Compared to that, a man was a mere janitor able to clean up a mess, but not much more.

But the moms also seemed too rarefied to approach.

Thankfully, a group of Jamaican nannies took me in, and I was overjoyed to finally be a part of a group. We would meet up each day at the park and I would hear tales of their lives growing up in Jamaica, and also how, after taking care of someone else’s child all day, they would go home to care for their own sons and daughters. I wish I could do those ladies justice here on the page as they were so important to me for a time. And yet I didn’t do them justice in real life, either. The moment a mom showed an interest in me, I moved on.

It happened unexpectedly. I was pushing Hardy in a baby swing and a mom began pushing her son next to me. She was incredible, playing with her son’s toes, doing underdogs, and even lying down on the ground beneath the swing, which made her boy laugh. It was from this position that she looked up at me and said, “Hi, what’s your boy’s name, mine’s is Elijah.”

The woman’s name was Jessica and she was a mixture of a New York city tough and an Ivory Soap girl. She had short black hair, pale skin and a tattoo of a dove on her shoulder. When I brought her home for the first time Cathlin said, “Oh, wow, she’s beautiful.”

I smiled. “Oh, really,” I said. “I never noticed.”

Cathlin punched me in the arm, but she was smiling too.

Jessica introduced me to a whole group of moms — Paula, Jee Yoon, Jen, Deb and Nim — and I quickly became a part of their gang. That’s the thing about parenting I have learned, how fast you become so much a part of each others lives. Friendships before this were gradual journeys, picking up tidbits about the other like scattered crumbs, and over months or years finally forming a tight bond. But with parenting everything is laid bare so fast and so much is shared that within an hour or two it is as if you had never lived without each other. We were also in a sense the walking wounded, sleep deprived, often unwashed and wrestling with lives that had been completely changed by the sudden appearance of our child. In a way we were like a series of life rafts lashed together to ride out a storm. My heart grows large thinking about those moms once again, their children, and their partners, most of whom I have not seen in over six years.

When our children turned about four years old and our second kids were born, we all moved out of New York city as quickly and as choreographed as if a curtain had come down to announce the end of the first act of a play. We moved to Massachusetts, Washington, California, the New York suburbs and Martha’s Vineyard. We soon found ourselves immersed in a new group of parents, the relationships made once again faster than I ever would have believed possible, and the memories of those who had been so close before were lost in the everyday scrum that is parenting.

At the end of the first day of school when I picked up the kids, I was still thinking about those old days in New York and the children of my mom friends. I have no idea what those other children even look like now, those kids who for a time I would have defended with my life, just as I would my children’s new friends.

I looked at Hardy, now with thick hair that cascades down to his back, his shoulders growing broader each year. How long until his voice changes, I wondered.

I felt so distracted and confused by all this that when Hardy reached out to take my hand as we walked to the house, the size of it surprised me and before I could stop myself I pulled my hand back away from his. By the time I realized what I had done, it was too late. Hardy had already moved on to play in the backyard, completely unaware that his father had fallen to his knees on the porch, fully aware of what had hit him.