It was 2004, and my then-16-year-old daughter Merry stood in the driveway of our Fairfax Station home listening to the din of cicadas gathering in the surrounding woods. “Do you realize, Mom,” she said, “the next time the cicadas come, you’ll probably be a grandmother?”

I did the math quickly in my head. “You’ll be 33 and your brother will be 36,” I said. “I’ll be 66.”

Seventeen years. A lifetime for a cicada, and a mini-lifetime for a human.

The previous time the cicadas had emerged, in 1987, I was six months pregnant with that nearly 17-year-old and we lived in periodical-cicada-free San Diego. We had just bought a $125,000 tract home on a newly laid cul-de-sac, and when I wasn’t working as a city hall reporter, I would spend long hours hiking through the San Diego Zoo, trying to wear out my then 2-year-old son. Our dog in both cycles was a black Lab, but one had been named Delta and the other Gem.

As I thought more about the life spans of the cicadas, and how they seem to define periods of our own lives, I began noticing that I wasn’t alone in wrapping my life into the Brood X cycles.

At a backyard barbecue in 2004, we stood around a friend’s pool, a couple of us fishing out wayward cicadas as they dropped into the water. Ed, an FBI agent and former pro football player, was one of the softies scooping them out.

“Hey, they’ve waited 17 years for this,” he said.

Pete, who was born and raised in the D.C. region, the epicenter of Brood X, could vividly recall where he was in his life each time the cicadas had emerged.

“The first time they came that I can remember, I was 11,” he said. The next time, he was a father of two. With this third cycle in 2004, he had four sons and his second was about to graduate from high school.

The day after that barbecue, I was at an afternoon college graduation party for my friend Andrea’s son, Jason. We sat on the deck, listening to the cicadas hum. I turned to Andrea, and another friend, Tami, and said, “Do you realize that this is about the time we met 17 years ago?”

We reminisced about how, as new neighbors in San Diego, they had pushed their strollers past my house, hollering hello while I stood outside with my then-toddler, Steve. We laughed about drinking cheap wine coolers in the front yard while our children, most of them still in diapers, played outside.

“Remember how Maureen and Chris would collect buckets of roly-poly bugs?” Tami said, laughing. “No cicadas, but plenty of roly-polies.”

Earlier that morning, I had walked around Burke Lake Park, and watched as family after family with small children had stopped to examine the cicadas frantically trying to get to trees to start their march upward and the 17-year cycle all over again.

“Look, Mom,” said one child of about 4, “I found another ‘chisada.’ ” The mom gently corrected him. “It’s a cicada, honey.” “Yeah, it’s a big chisada,” he replied.

I walked past, thinking that when the cicadas returned, in 2021, that 4-year-old might be graduating from college, and his mom would tell the story about how he called them “chisadas.”

And now with their reemergence, it is 2021, and another period of all of our lives has passed. Many of us here for the last appearance are gone, and many have been born.

And the prediction shared by my daughter, who is now also known as Aunt Merry, was right. I have a 3-year-old granddaughter who I am eager to tell about the “chicadas.” Her baby brother only 4 months old, won’t remember Brood X but he will hear the stories from his sister and (I hope) me when — like clockwork — the cicadas return in 2038.

Carol Sottili is a retired staff writer for The Washington Post and a certified amateur naturalist.