The definition, according to Wikipedia of this phrase is an “Ironically polite term for a woman who does not want her actual age known, e.g. one who is close to or just over the menopause."
Things which define women of a certain age are:
exceptionally gaudy clothing, homeopathy and aromatherapy, sensible haircuts, books on feminism, affairs with paper boys, and coffee mornings.
The whole genesis of the name Don’t Call Me Ma’am came from our musings about how women age and how we can offer support in practical, positive ways. “Women of a certain age” strikes us as such a demeaning phrase just as being called ma’am makes us feel old.
Obviously we all want to look and feel our best. In reality, provided there hasn’t been a drastic weight shift, most of us look the same as we did 20 years ago other than the onset of wrinkles and perhaps a change in hair color.
This came in from a woman we know. It seemed like an appropriate positive affirmation without being ridiculously Polly-annish.*
“When I look at you, I see that you look exactly like you, and it is wonderful to look at you and see the same wonderful person that I have known all these years. I think it is a very nice that you’ve updated your wardrobe and made some changes to your hair. The only difference between you then and now (other than your wonderfully increased wisdom and expanding wit) is that your face shows the new appearance of wrinkles.
But seriously, the luster of your hair, the shining smile, the twinkle in the eyes, the mischievous grin, is all there but so are the lines, get over it!”
*only people of a certain age even know what I’m referring to when I say Polly-annish.
From Wikipedia: The Pollyanna principle (also called Pollyannaism or positivity bias) is the tendency for people to remember pleasant items more accurately than unpleasant ones. Research indicates that, at the subconscious level, the mind has a tendency to focus on the optimistic while, at the conscious level, it has a tendency to focus on the negative. This subconscious bias towards the positive is often described as the Pollyanna principle.