I've just entered the final year of my 20s. As a friend informed me last week, I am not the kids any more. I disputed this. I am too the kids! But in the end I had to concede his point. Small children on public transport call me "the lady", not "the girl". ("Daddy Daddy, the lady is making faces at me"). Professors at conferences no longer assume I'm a postgraduate helper, and have stopped asking me to bring them tea and monocles. There's also an internal change, which, if anthropomorphised and given voice might scream: "You're nearly fecking 30 woman! Shouldn't you have accomplished something by now?"
Thankfully, Robert Redford has silenced my demons. At 76, he plans to step back from Sundance, the incredible independent film festival he founded in 1981. This is not because he wants to retire to an island and play celebrity bingo, but because he feels the festival no longer needs him, and he wants to concentrate on other artistic projects. His lefty political thriller The Company You Keep, opens in the UK in June. He also recently starred in Oscar-nominated director JC Chandor's dialogue free castaway drama, All is Lost – and his upcoming projects include an adaptation of Bill Bryson's travel memoir A Walk in Woods. At 76, Redford is on top of his game. He has unfailing political drive, and he's at the cutting edge of independent film-making. Most importantly, Redford is 2.62 times my age. I have loads of time to do stuff with my life.
But wait: Redford is just one man. What if he's the exception rather than the rule? This misgiving led me and two friends to spend an afternoon debating our top five artists over 70 (Redford included) who are rocking the socks, the Kasbah, and other rockable entities. We might not be the kids any more, but we've still got people we want to be when we grow up.
Theatre: Ariane Mnouchkine (2.55 times my age)
Mnouchkine has been the queen of the avant-garde since 1964, when she founded Théâtre du Soleil. I don't agree with all her philosophies about moribund European realist drama needing reinvigoration from the truly theatrical east, but this doesn't detract from the fact that her socialist, anti-conventional theatre collective basically invented immersive theatre, and Mnouchkine continues to shape the path of the western dramatic tradition. In the 21st century, she has confidently surfed political theatre's move towards testimony. For example, Le Dérnier Caravansérail takes six hours to interweave the stories of refugees from countries including Iraq, Kuwait and Serbia, without forfeiting Mnouchkine's lush sense of spectacle. In recent years, she set up Théâtre du Soleil sister companies in Afghanistan and Cambodia, and she continues to direct her own ambitious and challenging work.
Visual Art: David Hockney (2.62 times my age)
A pioneer of the queer, a man who flows dolphin-like through oils and acrylics, through Polaroid pastiches, through ingenious stage design, through prints, through portraits, and, of course, through swimming pools, Hockney could teach Madonna a thing or two about reinvention. In the past few years, he's created a significant amount of his work on iPads. For those clueless Luddites (read: me) who had doubts about the power of his new form, last year's exhibition at the Royal Academy, The Bigger Picture, blew us out of our backwaters and into the future. Adding extravagant philanthropy to his already impressive list of talents, last year Hockney gave paintings worth over £80m to his charity, The David Hockney Foundation, which aims to increase public appreciation of contemporary art.
Fiction: Margaret Atwood (2.55 times my age)
She won the Arthur C Clarke award, but she doesn't write science fiction; she's a lifetime poet of women's oppression, but she's not a feminist: complex, contrary and consistently astounding, Atwood is, like the Persephones and Penelopes who lace her oeuvre, legendary. I came to The Blind Assassin when I was 18, then followed her trail of cat's eye jewels back to The Edible Woman. I swallowed Oryx and Crake in one mouthful, but sucked on The Year of the Flood, trying to make it last. Now I am starving for MaddAddam. Feed me Margaret! Feed me!
Music: Tina Turner (2.5 times my age)
OK, this category was the subject of much debate, with Bob Dylan, whose Tempest is awesome, almost toppling the Queen of Rock from her throne. But, in the end, with the 73-year-old radiating cool on the cover of this month's German Vogue (making her the oldest Vogue cover model ever), Turner keeps her metal studded, leather coated sceptre. Reviews of her 50th anniversary tour move me to near-violent jealousy: the vicissitudes of her career formed a raucous, yet moving whole. Moving, because who among us doesn't have a Turner number on the soundtrack of their life? Her recent work has been low key, collaborative and spiritual, with a third Beyond album in the offing. But the Vogue interview shows she's not in retirement yet – she's just waiting for the right material before she re-invents herself. Again.
