I don’t know about you, but the whole “I’m a mom” thing took a really long time to sink in. Even when I had a baby in my belly, it still felt surreal and sort of impossible.

Later, when Lucy was a toddler, I was hired to write a magazine piece about mothers and daughters and the new knitting trend. (Remember that?)

As I was accepting the job, I said, “Yeah. My mom knows how to knit. I mean, she sews better, but I’ve seen proof of her skills with needles and yarn.”

There was a long silence on the other end of the phone.

“Uh,” the editor said, “You would be the mom in the piece.”

Later that day, as I was reliving my mortification, it occurred to me that it was taking me an awfully long time to believe that I was a mother. I wondered why. I’d given birth. Nursed the baby ‘round the clock. I’d changed diapers, swaddled her, rocked her, danced with her—everything that new parents do. So what was with me?

A few weeks later, Adam left town for a business trip to Japan. While he was in Tokyo, taking pictures of buildings shaped like mugs of beer, Lucy and I were going about simple our routine. We were in the car, driving down a tree-lined street near the University of Washington when I glanced in the rear-view mirror to admire her.

That’s when she started puking.

It was sort of like watching a fountain erupt, only more colorful. I pulled over, worried she might choke.

When I came around to the back seat of the car, she held her arms out for a hug. I looked at her, all covered with barf. I looked at myself, wearing a dry-clean-only wool coat. And then I leaned into the car, took her out of her car seat, and held her tight.

This maybe doesn’t sound like much to you, but I have a fantastically weak stomach. I couldn’t watch the second Austin Powers movie without getting queasy.

Covered in the stuff of my worst nightmare, I strapped myself back in my seat, rolled the windows down, drove home, and held Lucy until she stopped crying. Afterward, I bathed her and wrapped her in clean blankets—all before I cleaned myself up.

That was the moment I officially became a mom. I did something that at one point would have been impossible for me, simply because I had to.

The same was true for many moms I talked to. The details varied—Lois, for example, felt like a mom when she had to make the call to put down the cat. Nancy and Karen felt like moms when they had to watch their sick kids in the ICU. For Marjorie, it was when, during a bout of post-partum depression, she rallied enough to decorate the tree for baby’s first Christmas.

What this says about us, so reluctant to take the title mom, is that we admire the heck out of mothers. They’re brave and full of love and determination. How could we possibly think of ourselves that way without earning it?

The trials we face vary, and I feel for the moms who have to bear the worst of them.

But I’m glad we all instinctively recognize that the title of mom isn’t one given lightly. It’s one given to people with the courage to do whatever they must. The other word for these people is heroes.

No wonder, then, that so many of my favorite people are moms.

Here’s to all of them on Mother’s Day.

HAPPY MOTHER'S DAY from Cozi.