Joe Biden’s age isn’t the problem. We are.

Is President Joe Biden, at 80, showing his age? Of course, he is.

You see it when he struggles with balance and hear it in his faltering speech.

Unsurprisingly, a NewsNation poll released last week found that 80% of those responding said they’re “very concerned or “somewhat concerned” about Biden’s age.

But what’s the big deal?

Let Biden speak from a comfortable chair and use a walker when he has to go a distance.

The shame isn’t that Biden is showing his age. The problem is that the Democrats couldn’t find a promising candidate to challenge the Republicans and let Biden go home and get some rest.

Americans should be concerned if the medical professionals caring for Biden determine he can’t carry out his duties.

Otherwise, our concern is just ageism.

Ageism is one of the last acceptable prejudices, “so ingrained in our culture that we often don’t even notice,” according to the American Psychological Association.

Because of ageism, women in the spotlight must wear a ton of makeup to appear youthful, while men can age naturally without worrying about looking old.

After running through my 50s, surviving my 60s and slowing down in my 70s, I’ve learned an important truth: Every day, there is another challenge to overcome.

Aging isn’t for cowards.

Still, if you are blessed to be in your 70s or beyond, we need to hear from you now more than ever.

Many of you are now accomplishing more in your latter days than in your earlier years.

I just read an AARP magazine article about a woman who became a fashion model at 73. And there are remarkable stories about bodybuilders, adventurers and entrepreneurs in their 80s, defying the stereotypes of old and crotchety.

Don’t get me wrong. There’s nothing wrong with retirement.

After working most of our lives, it is reasonable to expect that at a certain point we will be able to kick back and do only what we want to do and not what we have to do to occupy space in this world.

But concerns about the solvency of Medicare and the seesaw economy have many of us putting off our retirement dreams.

That’s OK.

The delay might help jittery seniors overcome the retirement anxiety many seniors suffer when it is time to cut the cord.

Unfortunately, not every senior has a choice. Many seniors do not have children to help support them through this phase of life and have to work until their health fails.

But, as much as I want to kick off my shoes and let the world go by, I can’t. After a taste of retirement, I realized it is not in my nature to remain silent when the world is going to hell in a handbasket.

This new column I’ll be writing, called “Starting Over,” will segue into what’s next for baby boomers like me.

I hope it will be a place where they feel valued.

Instead of ridiculing seniors for being old, we should celebrate their longevity and learn from their experiences.

I don’t need a mirror to see that I am aging.

Every day, I run into subtle and not-so-subtle reminders that I’m coming closer to the end of this journey we call life.

I see it in the faces of well-meaning acquaintances who tell me how good I look for my age. I hear it in the voices of young men who call me “Mama,” even though they are strangers, and from grown men who address me as “young lady.”

So why am I writing about this now?

Because there is still a lot of work to do, and time is winding down. We don’t have time for “-isms.” We must prepare the next generation for what we know is coming.

Besides, at this stage of life, you begin to think about what you could have, should have or would have done differently if you had the chance.

While there are no “do-overs” in life, every day we wake up is an opportunity to start over.

Mary Mitchell is a longtime columnist for the Chicago Sun-Times. Her new column on aging and other topics will appear on Sundays.

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