I was a new mom at 36, and there was a lot about motherhood that terrified me. I had no experience with infants, nor did my husband, Michael. As happy as we were to be expecting, I was filled with fear and trepidation. How on earth would I know what to do?

So it was revelatory to discover that holding my new daughter, Gillian, was like being home.

In my arms her soft, solid warmth still felt a part of me, part of my body. Over the first few weeks the power of my love grew such that nothing could ever pry her out of my arms. I know this. I knew it once, anyway.

On the morning after Thanksgiving, 1998, Gillian and I were alone in the quiet house. She woke early as 10-week-olds do and smiled as I entered the room.

After our blissful morning cuddle, off we went, toward the stairs, ready to take on the day. Gillian was cooing in my arms and I was thinking about the leftovers and festive clutter needing my attention down in the kitchen.

And just at the top of the stairs … an overconfident step, slightly off balance, a moment’s distraction. My feet went flying, my hands grasping for the handrails in frantic reflex and instantly, shockingly, Gillian’s soft weight left my hold.

My vision was filled with her face, contorted in surprise but no fear — she didn’t yet know fear — floating down the stairway in front of me.

I had slipped at the very top of the stairs, a 14-step flight. As she flew down she looked up at me, her mouth an “O” and her eyebrows as far up as they could go, all the long way down. As I crashed down the stairs myself, clumsily and painfully, unfathomable thoughts crashed through my brain.

How? How could I ever have let go?

Our child would never grow up, Michael would never forgive me, the pain would be eternal.

I’d wrecked our family forever.

And then she landed. Feet first, face down, her tummy hit the edge of the bottom step as her head clocked the wall, right at the sharp edge of the wooden molding. I frantically finished my own descent, holding my breath and hearing only silence.

And then she cried. Somehow I managed to call 911 and somehow I got Gillian, still wailing, into her bucket-shaped car seat and made my way to the street. The ambulance finally came to take us away.

The questions began immediately. What happened? they asked. Is this your first child? Does she cry a lot? How are you feeling? Have you been sleeping well? Have you been sad?

I understood what they were looking for, but it felt appropriate to be judged and found wanting. Clearly, I thought, I’m unfit for this job. It’s wrong to trust me to take care of my own baby.

Gillian was fine. And forgetful, and forgiving. I wasn’t. Michael carpeted the stair steps and covered me with love and unstinting support. He never wavers from his affirmation that, yes, accidents happen and, yes, this was indeed an accident.

I was not so easily convinced.

The shame of having dropped my baby was — is — palpable. You what? You dropped your baby down the stairs? Other mothers can’t fathom such a thing. Of course not. Neither could I, before it happened to me.

We so often hear of tragedy — a hot car, an unlocked pool gate, the limits of a rear-view mirror — caused by devoted parents or caregivers. I’m more sympathetic because I think I understand a little bit of the dark shape of a life burdened with guilt beyond repair.

For those brief moments, as my daughter flew dangerously down a long, long flight of stairs, I was there, thinking I had killed my child. And I will never forget.

The Christmas pictures from that year show my wrist brace from my own injury, clear evidence of my carelessness. I walk down those stairs every day and shudder a little, and thank providence once again that we were lucky.

It took a long time but I eventually started to trust myself to keep my baby safe. Our second baby was born two years later, and we managed to get her through her toddler years unscathed. Yet I never felt fully relieved of the guilt until Gillian herself could understand the story and forgive me, and promise me she doesn’t remember a thing.

I do.