The author and three grandsons. “You do want to leave the world a better place,” she writes. (Courtesy of Gina Glantz)

When I turned 70 in 2013, I figured it was time to decide “What next?”

Shout at the news from my comfy armchair while wielding my TV remote? No.

Retire to a warmer climate? No.

Read Modern Library’s 100 Best Books? No.

Start an online community of activists dedicated to ensuring that women are always part of the public dialogue? Definitely yes.

As an inveterate organizer thoroughly unhappy about the paucity of female representation all around me — at conferences, on “top” lists, among media covering politics, and so much more — I could not resist doing something. And so by the time I turned 71, I had named my community-to-be — GenderAvenger — created a website and begun organizing.

In my younger years, I had managed political campaigns, conducted union organizing efforts and led a woman-owned consulting firm aimed at affecting public policy. I’d had my share of successes and disappointments, compliments and damnations. It didn’t take me long to see the advantages of leading an advocacy start-up in my dotage:

You have an outlet for disappointment about things that still haven’t gotten done. I am not the type to dwell on my mortality, but I do tend to dwell on what I wish would happen sooner rather than later. Now I have another opportunity to work on persistent issues with new, laserlike focus.

You know the sun comes up every day, so you fear mistakes less and are less consumed by criticism. As Esther Dyson says: “Always make new mistakes.” And about that criticism: So what? I have come to realize that it most often vanished from the mind of the critic far more quickly than it did from me.

You are not inhibited by ambition. You can do whatever you feel like, and the consequences be damned. There is no need to be careful about who might be offended. Not that I was all that careful in decades past. But, to be honest, there were times along my political career path when I veered away from what my gut told me to do and toward what I thought would be accepted by the — yes, male — decision-makers around me. All too often, women especially fear hearing “there she goes again” as an indictment rather than having their point of view considered legitimate. Concern about being pigeonholed can silence important voices in critical positions. (Think the White House, the boardroom, etc.) I have discovered that this problem doesn’t exist when you reach a certain age.

Corny as it sounds, you do want to leave the world a better place for your grandchildren/godchildren/all children. When my grandson was about 3 years old, he declared that he knew God was a woman because “God makes people, and only mommies can make people.” I want to do what I can so he knows he was right: God could be a woman ... or an expert onstage, a member of an elite group, you name it.

Your children can simply shrug off your latest passion translated into action. Having already suffered the consequences of being your child, they can legitimately say, “There she goes again.”

Your Rolodex (a 20th-century contact list) is big enough to find supporters to quickly get started, and you have accumulated enough chits to ask for favors.

You know from sad experience that the job won’t get done in your lifetime but there will be others to carry on. That’s why you know you need and want to get younger folks involved. Gender­Avenger’s co-founder is 20 years younger than I am; our webmaster, 30 years younger; and our director of communications, almost 50 years younger. You are not threatened by their knowing more than you about how to operate in today’s cyberworld.

Bonus reason: Numerous studies show that using your brain helps maintain your brain. Believe me, starting an online organization today definitely creates opportunities for mental stimulation. I’ve learned how to use new social media platforms. I have brainstormed about and tried new methods to engage folks in action. I have discussed issues with activists 40+ years my junior whose vocabulary and outlook are often brand-new to me.

Simply being online daily helps. A recently released study of nearly 2,000 men and women age 70 and older found that those who used the computer at least once a week — for email, Facebook, even paying bills — were 42 percent less likely to have memory and cognitive problems than those who rarely logged on.

As the author of the study, Janina Krell-Roesch, said in a statement when the study was released, “The results show the importance of keeping the mind active as we age.” I guarantee if you start a new organization you will keep your mind active!

Today, my post-70 project and I are thriving. Our social-media effort exposes gender imbalance through weekly action alerts. The GenderAvenger Tally, an app we developed, allows folks to quickly create a pie chart from a conference, reading list or whatever that shows the percentage of women represented, along with either a black cloud or smiling star, and can be instantly posted to Twitter or Facebook. We’ve also created GenderAvenger Halls of Fame and Shame to highlight famous and not-so-famous Avengers of the Week. Sen. Bob Casey (D-Pa.), Container Store founder Garrett Boone and writer Ron Fournier of the Atlantic are among the signers of our Male Pledge, which states that the signer will not appear on any panels where there are no women.

And I can see that this effort is starting to make a difference. After a GenderAvenger Action Alert featured Esquire’s July 2015 list of 80 books “Men Must Read” — 79 of which were written by men — the GenderAvenger community took to Twitter and Facebook expressing disappointment (dismay, really). We may not have been the only protesters, but we were definitely the most public. Several months later, in January 2016, Esquire published a new list, this time “80 Books Everyone Should Read,” which was accompanied by this apology:

“What can we say? We messed up. Our list of “80 Books Every Man Should Read” ... was rightfully called out for its lack of diversity in both authors and titles. So we invited eight female literary powerhouses, from Michiko Kakutani to Anna Holmes to Roxane Gay, to help us create a new list. Each participant made 10 picks. It’s a new year, a new We’re looking forward to reading and we hope you are, too.”

At 73, I am celebrating everything age brings ... except some of those irksome aches and pains.