You never forget the breathless phone call from a son-in-law and the words, “We’re leaving for the hospital.” Or the endless car ride to a maternity waiting room on a sun-kissed October morning for the wait of all waits: the birth of a baby.

And how does one ever, ever forget the moment when that son-in-law rushes out to say, “It’s a girl!”

It felt surreal, of course. Like a film run amok, a dreamscape, a bizarre waking fantasy. But there we were, meeting our first grandchild – and realizing that our daughter, our own firstborn – now had a firstborn daughter of her own.

Not even this rich and expressive language has the right words for this experience. Only the heart knows them.

There have been six more of those moments, all played out differently, yet feeling remarkably the same. And once – just once – I had the extraordinary experience of watching a child of my child being born. Nancy and her husband gave me that gift like no other, and thank goodness I didn’t chicken out.

Of all the magnificent moments motherhood brings, I insist that seeing daughters become mothers tops them all.

Nobody ever told me how it would feel to hold a daughter’s newborn in my arms and glimpse eternity in that scrunched-up tiny face. Try convincing any man or woman who has had that experience that there are no miracles. And just try holding back the tears of exultation, awe and wonder.

The moment when I learned that after three generations of a female dynasty, a baby boy named Samuel Ezra Friedman Zinn had entered our lives left me breathless, speechless and once again sobbing in a maternity waiting room.

A boy – a red-haired boy with blazing blue eyes. How had we ever lived without him?

Those babies of our daughters seemed to come in rapid succession. For years, it seemed, some Friedman daughter was pregnant. Each time the birth approached, I worried it couldn’t possibly match the time before. Each time, I was dead wrong.

My own learning curve was steep: I had to master the art of keeping my mouth shut about their birthing plans – bathtubs, doulas, midwives – my own grandmother would have fainted.

Then I had to master all that was new in babyland, from opening complex strollers to diapering baby boys…no small feat.

My daughters were my teachers. I sometimes wore their patience thin.

But through it all, I’ve had the profound privilege of watching that incredible transition: my babies with babies of their own.

We were not spared grief. Along the way, Amy, our middle daughter, lost a baby very late in her pregnancy. We never had the chance to meet Jackson, so yearned for and mourned. But when Emily, and then Carly, came to Amy in rapid succession, I watched this daughter and her husband heal.

I’ve watched my daughters sweat out those terrfying fevers that won’t break, those tantrums that seem to go on forever and those walks away from a kindergarten classroom where their most precious cargo has been handed over to a smiling usurper – the kindergarten teacher – who sends mothers away.

And soon, I’ll share the momentous leap into the unknown when Jill sends her first child – our first grandchild – off to college. There is no way to prepare Jill for that last hug, the one on some grassy quad when her arms will refuse to let go. She’ll find out for herself.

So as Mother’s Day approaches each year, I always pause amid the bedlam that is our annual celebration just to look around me.

While I’m presumably being feted as the matriarch, I’m always only half-there. I’m lost in the mists of time, the mystery of where those other years have gone, and the deep and enormous privilege of watching three grown women watch over their own.

Trust me – it doesn’t get any better than that.