How do we know when we're old?

I have a very glamorous, very gorgeous & in my eyes eternally youthful friend who splits her time between LA & London. She is a proper artist (as in exists on the proceeds from her art) hangs out with the likes of Oprah (yes THE Oprah) gets invited to all the cool parties & yet who mailed me today with the attached photo (from her LA "office" - yeah I could hate her too if only she wasn't so lovely!) claiming it proved she was now old. How did it prove she was old? She was wearing purple – and a hat! For the uninitiated I now have to reproduce Jenny Joseph’s genius poem in full.

When I am an old woman, I shall wear purple
with a red hat that doesn't go, and doesn't suit me.
And I shall spend my pension on brandy and summer gloves
and satin candles, and say we've no money for butter.
I shall sit down on the pavement when I am tired
and gobble up samples in shops and press alarm bells
and run my stick along the public railings
and make up for the sobriety of my youth.
I shall go out in my slippers in the rain
and pick the flowers in other people's gardens
and learn to spit.

You can wear terrible shirts and grow more fat
and eat three pounds of sausages at a go
or only bread and pickles for a week
and hoard pens and pencils and beer nuts and things in boxes.

But now we must have clothes that keep us dry
and pay our rent and not swear in the street
and set a good example for the children.
We must have friends to dinner and read the papers.
But maybe I ought to practice a little now?
So people who know me are not too shocked and surprised
When suddenly I am old, and start to wear purple.

I have just glanced down at my keep warm gear today – which comprises pale purple t-shirt, purple cardi & multi coloured purple scarf. And if I am honest I have grown quite fat in my domestic bliss ... my father actually gave me a stack of Weight Watchers recipe cards recently. Discreet huh? And I spend most of my income on good red wine – that's quite close to pension & brandy n'est ce pas? Maybe I just hadn’t noticed I was old ...