This weekend, my family is throwing a surprise birthday party for my grandmother. A surprise 90th birthday party. Setting aside the question of whether one should surprise a 90 year old with anything, least of all a room full of people yelling “surprise”, the party has got me thinking. A lot. The first question is whether I should drive 250 miles, each way, with my small children in the backseat, and then drive back the next day, so that we can attend the party. It’s a long way to drive, at an inopportune time of the year, and we’ve all been sick for the last few weeks. We’ve been feeling better, but the very idea of a trip right now – and that long winding drive — exhausts me. But 90th birthday parties don’t come around that often, and everyone else will be there – Baba’s children and grandchildren and great-grandchildren, dozens in all.

The next question is predictable, given my propensity for older mother math. Will that ever be me? I’m willing to buy into the idea that I may live to be 90, but will a party thrown for me threaten to overflow the common room at my senior center? Is it mathematically possible for me to have great-grandchildren by age 90? Or to have great-grandchildren at all?? Let’s see, if my eldest gets knocked up at 16, and her daughter gets knocked up at 16 …

Baba was a mother at 21, a grandmother before 40 and a great-grandmother by 60. Thirty years later, great-grandchildren are still being added to her family tree, most recently via my youngest daughter, now 1. And this weekend she’ll be able to look around a room full of people she has helped to mother and raise and support, and I hope it will feel wonderful to her.

My goal is not to be the trunk of a massive family tree, it really isn’t. But I do like to imagine that, despite my late start, I’ll live to see my two children have two children, and their two children have two children, so that, aged 90, I might be in a room with my 14 progeny and their loved ones. The math isn’t really impossible, as long as not everyone waits as long as I did to have kids. If they do, I’ll have to live to 105 to see a great-grandchild, I think (though math was never my strong suit).

Mostly, I’m in awe of my Baba. She is in decent health, though we’re all wary enough to imagine each visit could be our last. Each time, I take photos of her with my children, who are still too young to appreciate much about Baba besides the jellybeans on her table and the painted Ukrainian Easter eggs left out, year-round, in a basket beneath her television. I’ve probably waited too long to give my children much of a memory of my grandmother, born on a farm, raised in poverty, successful despite the odds, and proud of her family. But I know, at least, that I didn’t wait too long to give my Baba two more great-grandchildren. She is by no means too old to enjoy babies and toddlers. She delights in making them laugh, in stemming their tears with tricks or tickles or treats. Seeing her shed years in their presence gives me hope that while I may never be a great-grandmother, it is in my genes and my heart to be a very good grandmother.