It was never really clear, the mystical thing that I was to understand. If I could just get it together enough to have a kid already, I could finally know what I desperately needed to know.

I’m sorry. I’m sounding sarcastic. I haven’t been sleeping.

I think that’s one of those things I couldn’t have possibly understood.

OK, I get it now.

This year I will celebrate my first Mother’s Day with a baby of our own in our house (and in my arms and in my car and in the bathtub and in her carrier walking with me across the cow pastures) and I can’t help but notice that over the past five months it’s felt like I’ve become a part of this big, new and welcoming club.

My Sister-in-law, who is busy raising my three nieces. She sent us home yesterday with five big bins of girl clothes. God bless her.

I walk through the grocery store with the baby strapped to my chest, wiggling and drooling and smiling at the stranger in the dairy aisle who smiles back. “Two teeth already! How old is she? Wow, that’s early! My son didn’t get teeth until he was almost a year. He’s 21 now. They grow so fast …”

And we stop there, holding our milk cartons, feeling compelled for some numinous reason to share with one another our most intimate birth story, the struggles we had or didn’t have with feeding, the joy of the first smile and ugh, the sleepless nights, the stranger so eager to reflect and relay, and me, a new mom, hungry to know that I’m not alone in the joy and, more importantly, the challenge.

“She’s precious,” she says. And I beam with pride as I move on to the cereal.

Working men in muddy boots push past us with carts full of chips, burgers and pop. One stops to take a peek at my baby’s chubby cheeks. His daughter is 3 and back home in Tennessee. Before I had Edie I would say, “I can’t imagine what it would be like to be away from her.” Now my heart breaks for him.

Until five months ago I only understood motherhood from the perspective of having one. And I have a great one. One of the best. But I always thought she worried too much. I’ve been telling her that since I was a little girl. Don’t worry, Mom. Don’t worry!

Now I know what an impossible demand I was making on her as I pulled on my boots and went out into this big, sharp and dangerous world, my little sister trailing behind me.

Asking her not to worry was like asking her not to breathe. I get it now, Mom. I haven’t stopped worrying since the moment I found out I was pregnant. And when I’m done writing this I’m ordering Edie a full-body helmet.

Because the big, sharp world is dangerous, yes, but now I get to watch my baby discover it, and I think I might have taken for granted what a gift it is to have hands that can touch and eyes that can see and a voice that can laugh at the wonder of it all.

Apparently with all this motherly worry comes waves of overwhelming gratefulness.

Yes, they told me I’ll understand when I have kids of my own and, finally, here I am discovering what being a mother means to me.

And while the birth of my daughter has somehow given me a big happy welcome into this warm and open club of parenthood, after such a big discovery, this Mother’s Day I don’t have anything more profound to say than this:

Thank you, Mom, for worrying.

Thank you, Baby, for being born.

And to all the mothers-in-waiting, may your children find you.