"You're only as old as you feel," says my mother. She's 67.

"True enough, until you catch sight of yourself unexpectedly."

We cackle down the phone. We've both done it, of course. Walking down a street, you look into a display, and instead of the items inside the store, you see yourself mirrored in the glass. Unexpected, your response is as to a stranger. For a split second, you're not seeing yourself through the filter of your consciousness, your self-perception.

This can be a rude jolt. A bakery has a large mirror on the wall behind the till. A quick glance up, "my GOD, that woman looks severe." My God, it's me. How mortifying. Paste a smile on that face, you forbidding harridan.

In from the cold, glance towards the window, encounter a mirror I didn't know was there. My SKIN. What's happened to my skin? Isn't the cold supposed to shrink things? Shouldn't it make my face smoother? Another ten years, I'll have jowels, so help me. Gawd.

But sometimes the jolt is a good one. Just having had my hair done, I glance to one side to speak to the friend beside me, and see myself in the mirrored pillar behind her. "Wow. What a gorgeous woman." And it's ME. Ha!

Which has me wondering: what is the face I expect to see? If I'm only as old as I feel, what age is that? My self-perception and reality are obviously a few years out of synch. How many?

I suspect about ten years. I think were I to see my 35-year-old face smiling (or, as the case may be, glowering) back at me, I wouldn't be at all startled. Which, were I suddenly blessed with my 35-year-old face, would be rather startling.

Would people react differently to me? And if they did, would it be an improvement or a diminishment? Would people see the younger woman as more vibrant, more vital, more "with-it" and thus more worthy of attention? Perhaps, but I have my doubts.

The younger woman certainly got more sexual attention, more global, universal awareness, but the 40-something me gets her fair share. Just from a different, more specific audience.

My perception is that I get more respect now than I did ten years ago, but perhaps that's a function of my increased self-confidence and greater depth of wisdom. (Yes, I think I have some small store of wisdom, accumulated through the years.)

In which case, I am as old as I feel. Which is my real, my chronological age. My well-earned, well-lived, well-considered age, with its gray hair (diligently covered), its wrinkles (signs of the life lived within this skin), its occasional hot flashes (power surges?). And its very rich interior: the experiences, the memories, the time spent thinking, evaluating, reading, learning, considering, the richness of perspective, gleaned in bits down the decades. The interior. Which, in the end, is far more significant than the exterior.