Getting older is something that happens to other people. As children, 20 seems impossibly old, thirtysomething is unimaginable. But when we reach our twenties or thirties, our notion of old age moves up a decade, and then another, and another. Our denial is hardly surprising, given that our society tends to equate age with loss - of looks, energy, fertility, health, potential. Ageing, we're told, is some- thing to be disguised with creams, Botox and hair dye.