With horror, I realized one morning that my daughter’s motor and language skills would meet and then surpass her father’s as they progressed in opposite directions.

In those first couple years of childhood, there are so many milestones to celebrate: when they smile for the first time, roll over on their own, take their first steps, say their first word. Every inch grown, every pound gained and every skill mastered leaves us breathless with pride and contentment, marveling at this little life.

I remember how we rejoiced at every one of those well-child appointments as the pediatrician checked off each milestone met.

My husband, Steve, had struggled greatly with learning disabilities his entire life, and he had required braces on his legs as a baby. He was so relieved the afternoon our daughter was born with perfect little baby legs, no interventions needed. He was thrilled when she began walking at 10½ months, and he felt immense relief at how quickly her vocabulary expanded and the ease with which her words became phrases and then sentences.

She was healthy and growing and meeting all those innumerable milestones, so while I was pleased, of course, I never really worried about her abilities or pace as much as Steve did. That was also probably because I was too absorbed with worrying about him.

At the exact same time that our daughter’s world was exploding with possibility, Steve’s physical and cognitive abilities were slowly diminishing. Our daughter was born almost exactly 18 months after Steve was diagnosed with a brain tumor at the age of 27. His original prognosis was five to 10 years because he was so young and otherwise healthy, so we took that leap into parenthood, briefly shedding the weight of everything that lay ahead.

Life was good for a while. Steve was able to continue working until our daughter was 8 months old. The first radiation therapy was only for six weeks, and he didn’t require another brain surgery until she was 18 months old. There was a brain injury rehabilitation center nearby that could manage all his therapies: physical, occupational, speech. The first chemotherapy he tried was oral — so he could take it at home, not hooked up to an IV in the cancer center more than an hour from our home and where we already spent far too much time — and the side effects were tolerable.

When our daughter was 2½ years old, however, things began rapidly going downhill. Recurrent treatment-induced brain swelling, a veritable cocktail of seizure and cancer meds, and tumor progression all took their toll. By her third birthday, Steve was struggling immensely with speech and mobility, had been homebound for nearly a month and had started hospice.

Somewhere along the line, her abilities had eclipsed his; I hadn’t even noticed that pivotal moment.

While she sat in his lap happily chattering away, he often struggled to say single words, even our names. Though he knew exactly what he wanted to say, his aphasia was often insurmountable and heart-wrenching.

Slowly, I watched life work in reverse.

When Steve could no longer walk, we used his wheelchair to move him about the house. As his grip weakened, we enlisted plastic cups with built-in straws. He used our daughter’s toddler toothpaste so we could brush his teeth easily anywhere in the house and we didn’t have to worry about him swallowing it. At mealtimes, I tucked a kitchen towel under his chin to catch spills and lost spoonfuls.

In time, he could no longer feed or dress himself, and then he could no longer get out of his hospital bed, even with my help. Before long, he could no longer chew or eat real food.

I spooned soft foods into his mouth, a teaspoon at a time. We switched his medications to liquids, which I administered via large plastic syringes, giant mirror images of the ones I used to give our daughter her fever medicine when she was sick.

Eventually, he could no longer help lift his hips so I could slide on a clean brief. In his hospital bed, I bathed his body with gentle soap and a warm washcloth. As with a newborn, I often checked to be certain he was still breathing. His eyes opened only briefly and he slept for hours that felt like days and then became days. And then, quite suddenly, it was over.

Very much like the birth of a child, a death, even one so acutely anticipated as Steve’s, is not something you can ever really prepare for. It doesn’t matter how many books you read, what others tell you to expect or how many preparations you make. Both events still come as a bewildering, world-stopping shock.

Steve died two months after our daughter’s third birthday, seven months shy of the short end of his prognosis.

And now, so often, the milestones I think about are the ones that she will meet without her father: the first time she rides her bicycle without training wheels; her first day of kindergarten; her first broken bone, flat tire, broken heart.

Under the scrutiny of grief, even the most mundane achievements take on enormous significance. I often want to tell him the things she is capable of that seemed so laughably far off when he was alive. She was so little the last time we were all together.

She can dress herself now, and she gets her shoes on the correct feet 70 percent of the time. She loves to take on tasks around the house, such as filling the cats’ water bowl when it’s empty — but not too full, she reminds me, so it doesn’t spill. And when it’s time to stack wood for the winter, she likes to hand me the logs, one by one, so I can fit them together like a puzzle before her eyes.

At her request, a few weeks ago I cut her long hair to shoulder-length. My heart caught in my throat: She now looks so much older, and every night she stands before the mirror to brush it out, all by herself.

The big milestones still often come with a wave of sorrow, and sometimes the little ones do, too. I don’t expect this to change.

Every day she gets bigger and stronger, taller and smarter. And now I await another eclipse: the day when our daughter will have lived longer without her father than with him. The moment will come when that gap widens, irreversibly, on the other side of her life, and that will be a different kind of milestone to contend with.

Sarah Kilch Gaffney is a writer who lives in Vassalboro. You can find her work at www.sarahkilchgaffney.com. This piece first appeared in The Washington Post.