Dignity and gravitas are qualities that we rarely expect to find in our celebrities, but at age 78 and more popular than ever, Maggie Smith isn't our typical celebrity.

America has fallen in love with this silver-haired actress. Why do I watch Downton Abbey? Maggie Smith. When you get right down to it, it's Downton's indomitable matriarch who keeps me—and quite a few others—coming back for more. The younger women on the show may get the exciting storylines, designer gowns, and photo shoots, but it's their grandmother who inspires me and my friends to write Facebook updates declaring, "I want to be Maggie Smith."

Of course, there's a distinction between Maggie Smith the actress, and Lady Grantham the character, but in the public mind, the two have largely become inseparable—all the more so because Smith, herself a British dame, has made a habit of playing such "biddies," as she calls them.

On any screen, large or small, the sight of that angular face with its piercing eyes lets us know that we're in for a distinctive experience, and a highly enjoyable one. Viewers relish her biting wit and the occasional glimpses of the vulnerability underneath, not to mention the awe-inspiring aura she seems to carry with her. "Old people are scary" is how Smith herself put it on 60 Minutes, with characteristic bluntness.

For Maggie Smith and her characters, that very scariness seems to add to the attraction. Though Professor Minerva McGonagall in Harry Potter puts forth a stern face and matter-of-fact demeanor, we see her as strong and caring. It helps explain, I think, why audiences on both sides of the pond have fallen so hard for Smith.

Our media is forever making idols out of the young and sexy—often pushing sexiness on them before they're out of puberty. And those who can maintain their sex appeal, and their shock value, the longest are the ones who get to stay popular. When an older actress makes a comeback here—Betty White being the most famous example—it's often because of a willingness to get down and dirty.

Maggie Smith may drop a curse word now and then (as in her latest movie, Quartet), but with her, the curse words aren't the point. People watch Smith to see a multifaceted performance and a strong persona, not to see how many smutty jokes she can make. With her portrayal of the Dowager, she makes old age look classy.

Though many of us tend to dwell on the quaintness and charm of its bygone era, Downton Abbey is set during a period of rapid change. Older members of the aristocratic Crawley family have fond memories of Victorian days, while younger ones are bobbing their hair, trying out various careers, and running off with the chauffeur. New freedoms and new ideas are opening up what was once a narrow and restricted world. The Dowager Countess's acidic running commentary on the proceedings, then, is more than just comic relief. With her old-fashioned perspective and her stiff upper lip—"Don't be defeatist, dear, it's very middle-class"—she reminds us that some values are timeless and should never be discarded, even as we're attempting to keep up with the times.

Not that anyone could justifiably accuse the Dowager of living in the past. Despite her struggles with swivel chairs, telephones, and the concept of a "week-end," she is very much involved in the present. She has strong opinions and equally strong affections; for many viewers, the Dowager's devastation after her granddaughter's death offered one of the most moving moments of season 3. She'll fight for her principles, but she has the ability to yield graciously when convinced that she may have been wrong. (Even though it takes a lot of convincing.)

The Dowager Countess may not exactly have grown old gracefully, but she is a stellar example of growing old with dignity. Her age, in fact, lends her a gravitas that anchors the show. Maggie Smith has been playing characters who get their own way through sheer willpower and charm ever since her breakout role in 1969's The Prime of Miss Jean Brodie. But as was emphasized in the 60 Minutes interview, only now, in her seventies, has that gift brought her global celebrity.

For me personally, there's a lot to be learned from such a character. As middle age creeps ever nearer, I find myself looking for older role models—the kind of role models that it's sometimes been hard for me to find in my own extended family. My paternal grandmother, for instance, seemed to have it all: faith, family, a highly successful business, a multitude of talents, a home full of beautiful things, enough time and money to travel all over the world. And yet she was mired in bitterness, obsessed with the few opportunities she had missed.

The scary thing is, I get it. I can see the same tendencies in myself, and I worry about ending up the same way. I need to be reminded that it's possible to grow old and still be a whole person, with passion, purpose, an active interest in life, and an ability to see its funny side.

The Bible tells us that "the silver-haired head is a crown of glory" (Prov. 16:31, NKJV). I think our affection for Maggie Smith proves that, deep down, we still recognize that fact. Old people may be intimidating, but Smith is living proof that old age doesn't necessarily have to be.