The first time I ever felt like I was “over the hill” was on my 26th birthday.  That day I became ineligible to be Miss America, because I was too old. And that was so long ago that the pageant had not yet dropped its age limit to 24.

Truth be told, I never had the figure or the inclination to enter a beauty pageant. But there was something disconcerting in realizing that even if I did start frequenting gyms and beauty salons, I would never be “your ideal,” “the queen of feminity” or “the fairest of the fair,” as the Miss America song goes. It felt so much better to reject the pageant than it did to have the pageant reject me.

So the announcement last week that 41-year-old Jennifer Lopez had landed the cover of People magazine’s “Most Beautiful” issue was welcome news, even though this selection — like all judgments of who or what is beautiful — comes from the eye of the beholder.

A precise definition of beauty has eluded humankind for centuries. John Keats boiled it down to “beauty is truth, truth beauty.” Pre-Raphaelite painters had a certain vision of beauty; Hollywood plastic surgeons have quite another. National Geographic tried to tackle the subject in an article titled “The Enigma of Beauty,” and the Victoria and Albert Museum in London is focusing on “The Cult of Beauty: The Aesthetic Movement 1860-1900” in an exhibition that runs through July 17.

But when it comes to women, society’s definition of beauty has been closely linked to youth. Just look at fashion runways, where teenage models too young to enter the Miss America pageant display clothing meant for women who are too old to be Miss America.

In the 1980s, a 41-year-old woman never would have been dubbed “most beautiful” and would hardly have been considered capable of being a TV personality. In 1983, Christine Craft sued a Kansas City television station, contending that she had been removed from her news anchor job because her bosses decided she was not attractive enough or deferential enough to her male co-anchor. She was 38 years old. Certainly it would have been unthinkable back then that 65-year-old Diane Sawyer could anchor ABC World News.

While there have been plenty of advances in this area, some women still face the tyranny of advancing years.  In 2008, three Kansas City newscasters over age 45 sued their TV station – the same station that Christine Craft sued — claiming age discrimination. “Even unaffected newsroom employees have commented about the publicly humiliating and degrading treatment of women over 40,” the lawsuit said. The case was settled out of court last September.

Although age remains a factor for many women, Jennifer Lopez represents a significant milestone. “I feel happy and proud,” she said. “Proud that I’m not 25!”