When I was 26 and my mom was 52, we went backpacking together in France and Italy. We took the train, hitchhiked, stayed in youth hostels – the whole thing. It’s not that I’m abnormally attached to my mom – really. The year before I’d done Europe with my best friend, backpacking, youth hostels, Eurail pass. But every time I’d see something great or funny, I’d be thinking, I wish mom could see this. Because she’d never been overseas, but would have loved everything.

Backpacking through France and Italy was the start of our travels together. We did Australia next, then Greece, then Mexico. Always on a budget. I’d be in a phone booth, booking our accommodation for the next night, debating the guidebook entries, the one star versus the two star. And she’d be beside me, making whimpering noises, like a hungry puppy who just needs ONE NIGHT of a two star. One night with a private bathroom. But she was a seriously good sport about it all.

A few months after our European trip, my mom became a grandmother – to my brother’s first child, a son. And 18 months later, to his daughter. They got this great, young, fun, adventurous grandmother. She was still teaching, and would appear in their classrooms now and then as a substitute teacher, she was that young. Summers she and my dad spent at our family’s remote cottage, swimming and canoeing and fishing, and the grandchildren – my brother’s kids – spent their formative summers there. One March weekend, she and I dropped chocolate Easter eggs into the snow in the woods behind the cottage, and then were shocked when the kids, then 5 and 3, found them as they snowshoed along. Imagine the Easter Bunny traveling so far to leave them chocolates!

My parents sold the cottage the summer I was pregnant with my first child. More than a decade had passed, and they were getting older. Little repairs and odd jobs became onerous, and major work – shoring up the building’s foundation, replacing a dock – became crushing headaches. My brother’s family bought their own cottage.

A year later, shortly after the birth of my daughter, my mother’s doctor reported that her long-time heart murmur had turned into an enlarged heart, the leaky valve now dangerous, with surgery needed sooner rather than later. We got one more trip in before the surgery – she accompanied me to the Democratic National Convention in Denver, babysitting my infant in the hotel while I was out listening to speeches, the three of us sightseeing when it was all over.

She survived the surgery, though recovery was hard and painful and slow. She’s nearly 100 percent now, the only reminder of the trauma being the tray of pills she sorts weekly, an occasional shortness of breath, and a new appreciation of carpe diem. When my girls are in her lap, Claire interrupts storytime from time to time to say “What’s that sound, Grandma?” – her only awareness of the ticking ceramic heart valve and pacemaker hidden under a surgical scar.

My parents are still young, fun, lively grandparents to my girls. But the difference between 52 and 65 shouldn’t be underestimated. My mom still goes swimming with us at the local pool – and still goes down the water slide. But she’s sold her ice skates. My dad has sold his snowmobiles, so my girls will get their first rides from their uncle, not Grandpa. They spend their winters in Arizona, not hiding chocolates in the snowy woods at the cottage.

My decision to have my children late in life obviously gave them an older mother – will I be up to backpacking through Europe with a grown daughter when I’m 65? But it also gave them older grandparents. It doesn’t matter much yet. But when my girls are in high school, my parents will be nearing 80. Will they be there to see them go to university? Will they be there to see their great grandchildren? My decision to be a midlife mom has made the math nearly impossible for many of the things I took for granted – I still visit MY grandmother, who lives independently, tucks rolled up money into my pockets when I depart, and delights in her many many great grandchildren.

But I’m dancing around the real issue. While I regret the limits I have put on the relationship between my parents and my children, the grandchildren I feel most guilty about are my own. The ones my girls will (hopefully) have, some 20 or 30 or 40 years from now. Like every older mom, I do a lot of math in my head. If Claire has a child when she’s 35, like I did, I’ll be 70. Which makes me nearly 90 when my first grandchild is graduating from high school. Will I still be able to babysit infants and toddlers? Will my grandchildren find me hopelessly slow and sickly? Will they visit me at my house or in a nursing home?

For now these remain worries for a later time. Life is still full of diapers and Sippy cups and storytime. I need to focus on being an older mother before inventing problems for my grandmother years. And there is an easy way to be a young, hip grandmother. The next time someone looks at me, looks at my kids, and says “Your grandkids?” (Yes, it has happened), I can just nod, pat my grey hair, and smile proudly.