It starts with walking across the street.

“Can I go play at Lyla’s house?” she asked.

Just two weeks ago, my 5-year-old daughter walked across the street, hand in hand with her neighborhood friend – an 8-year-old – after assuring me she was ready. “I know what to do. I will look both ways.”

This moment was a natural progression of the laid-back, beautifully slow evenings we’ve enjoyed all summer. Lyla’s house has a tree fort and chickens, tomatoes that fall off the vine and ice cream bars in the freezer. Their friendship is the sort I remember from my childhood – before iPads, before we were afraid to play outside, before we worried about getting too wet or too dirty or too anything. It’s a friendship that has blossomed over bike rides and searching for pocket treasures and chasing down the ice cream truck. As the parents to the youngest kids on the block, my husband and I have been witness to it all. Each night, the neighborhood kids wait on the sidewalk (and sometimes on the porch) until their friends come home for the day. They bike and play and laugh until the moms come out, announcing dinner or bath time. There is always an adult watching it all, making sure the littles don’t cross the street alone.

But this time it was different. She asked me, specifically, if she could go alone, across the street, to a house we have been to several times before. And though the question wasn’t surprising, it caught me unprepared. I was taken aback, surprised at the sudden wave of emotion that kicked up inside me like the sand in an unexpected undertow.

“Sure,” I said. “Please hold Lyla’s hand. And when I come for you, it’s time to come home.”

She turned quickly, beaming with pride, and walked toward the street, hand in hand with her sweet friend. I watched as she carefully did what she promised and looked both ways, and then ran across, her newfound freedom unfolding like wings.

As I stood there, I felt the tears well up faster than I could make sense of them. I thought about kindergarten, how it was coming so fast. And all I could choke out as my husband looked at me, tenderly amused, was, “It all starts with walking across the street, doesn’t it?”

*****

Here we are two weeks later, on the eve of the first day of kindergarten, and those tears keep threatening mutiny at the most inappropriate times. My girl is so excited. At last night’s meet and greet, she met her teacher and ran to her with an embrace. She meticulously placed all her school supplies in their respective piles. She wrote her name on everything she could. My girl – the shy, soft-spoken, sensitive soul we love – walked around her new classroom confident and composed. It was clear, she is ready. Never once has she said she is scared. Never once has she asked to stay home. She’s defied every expectation I had of easing this transition, demonstrating that, in fact, it’s me that needs to be eased.

So I try to hide these tears behind genuine excitement as my heart swells with pride and aches all at once. Suddenly the paradox of motherhood is glaringly apparent: we strive every day to raise well-adjusted, happy and healthy human beings. If we are successful, we send them off, and a piece of our heart goes too.

When I was younger, I never really understood the moments my mom cried when I embarked on an exciting new challenge. Going off to camp, leaving for college, moving across the country, getting married… all the moments in my life that were hallmarks of my own self-discovery and success seemed a little bittersweet through her eyes. I chalked it up to being her only child, or to her getting older, or to the unpredictability of emotions. Little did I know how much more complex it actually was. What I realize now, as a mother myself, is that those tears are a visceral reaction to the heartache of motherhood. It’s an ache that isn’t simply boiled down into one specific emotion. It makes no rational sense and it’s another one of those parenting mysteries no one ever warns you about.

Five years ago, in the labor and delivery unit at 10 o’clock at night, as a spring snowstorm picked up speed, I gave birth to my first child. With one final push she slid into the world, letting out a single high-pitched squeal. They placed her on my chest and in that very moment I knew what they meant when they said part of your heart now lives outside your body. It’s a feeling not easily conveyed in words: suddenly you feel complete, like you've just been re-introduced to a part of yourself you were unaware of, but was there all along. Looking down at the miracle of a baby resting at your heart, it feels as though she is as much a part of you as your sturdy hands or your messy mom hair. Yet at the same time it feels like a part of you has moved into another body to walk the world on her own.

The first months of life together are symbiotic. Your rhythms sync. Your body attunes to her every need. You wake before she cries, knowing she will need to eat soon. Sure enough, moments later she cries out for you. As your child grows, your mom spidey-senses grow too. You can sense when she is hurt, or sad, or causing trouble. When she hurts, the pain is yours, too. You can anticipate her every move, you know what she needs before she can articulate it. She looks to you to gauge her security in moments of fear and runs to you when she wants to feel safe. She tests you more than she tests anyone else. You advocate for her and protect her. And you love each other fiercely, unconditionally.

Then suddenly it’s the night before kindergarten and it’s the first time she will have to navigate the world on her own. She will have to find her own seat at the table, make her own friends, stand up for her own needs. She will have to open her own juice box. And it’s thinking about that stupid juice box that brings you to tears, making you feel utterly ridiculous.

But it’s not actually the juice box. It’s the warp-speed memories that flood your consciousness – memories of holding that small baby and knowing exactly what she needs to thrive. It’s the feeling of being propelled forward, tumbling fast-forward through time, suddenly feeling like college is only a few short years away. It’s the reminder that time is so very fleeting, despite the fact that just moments ago you wanted to pull your hair out. It’s all the questions: Did I prepare her enough? Did I do a good job? Will she be happy? Will the world be kind? You are suddenly caught in an instant where time pitches you both forward and backwards all at once. The part of your heart that she carried with her into this world is the only part of you that will walk with her into that classroom, and you must trust that it is enough.

It’s the night before kindergarten. And now I get it. I understand that the heartache of motherhood is not one-dimensional. It isn’t solely sadness, or grief or even melancholy. The heartache of motherhood is almost always most potent in moments of pride. It mixes with excitement and happiness and relief and hope into a multi-faceted prism of emotions that can only escape the heart through tears. It’s an ache that comes from expansion; that little piece of my heart that my child carried with her into the world has found its legs. And as she walks forward into her own life, in this moment and every other moment like it to come, my heart will be there with her, soaring and expanding alongside.