Monday mornings have involved an emotional whirlwind since I took up piano lessons: fear, every week, as I wrestle with the instinct to cancel my 8.45am slot; a degree of humiliation as I take to the stool as its eldest and yet least able client; frustration almost to the point of tears when I can't decipher my All-Cows-Eat-Grass from my Every-Good-Boy-Deserves-Football in time to carry a tune; a glow as I fall incrementally more in love with my octogenarian teacher Patricia, don't get me started on the euphoria of transgenerational friendships, when she applauds the slightest achievement; and soaring elation (combined with deep relief) when I leave, desperate to get home to practice. 

I turned 50 on December 25th last year (a Christmas Day birthday has been a lifelong thrill, awarding me whooping adulation from anyone from medics to passport officials), so I elected to list 50 things I wanted to do this year, some free and easy, some more ambitious and expensive. Obviously there's hardly been time to complete the list, let alone act on any of it. But piano lessons have, delightfully, stuck. 

Music lessons were bad in the old days. I have vague memories of duress-laden sessions when I was about 5, followed by agonising guitar lessons at boarding school from a shower-averse man called Malcolm who used to fall asleep while I struggled through Oh Give Me a Home Where The Buffalo Roam, then sat agonising about whether I should keep playing or creep away. But since February, every Monday I find myself sitting next to Patricia for 45 minutes and, when we aren't giggling hysterically at how terrible I am at it, I've very slowly started to be able to do it. And I've never felt joy like it. 

The pleasure is multifaceted. There's the iterative sense of achievement, every five minute session at home leaves me feeling as if I've meditated, been for a run and had a glass of wine, with the additional satisfaction of my brain neurons firing like never before. I find myself drawn to the corner of the kitchen to practice in spare moments, where before I might have reached for my phone. Even better, it tempts my children over, they budge in beside me to rekindle the knowledge I forced on them in their own early years. Or they just laugh at me, then quietly congratulate me on any slight improvement, which makes me feel completely fabulous as I stumble through a basic nursery rhyme. 

There's vicarious joy in it, too. The reaction from people I tell ranges from "I LOVE that, I'm going to do it" to wistful WhatsApp messages arriving later from friends who've decided on painting lessons, or a solo trip, or investigated the possibility, at last, of doing something utterly for themselves. Garden designer Melissa Jolly started pottery lessons. "It was addictive immediately," she says. "No matter how busy life got, I never, ever cancelled." The wonderful, inimitable fashion matriarch Joan Burstein, who died in April having celebrated her 100th birthday in February, took up daily Scrabble matches (accompanied by a glass of Champagne) at the age of 95 and won almost every day. "With occasional cheating," smiles her daughter, Caroline Burstein Hammond, another midlife ceramicist. One girlfriend learned to row and became slavishly loyal because of the effect it had on her mentally, physically and socially; another started formally helping friends with their wardrobe edits to get herself out of her own head and house. Once her children reached a certain age, a new confidence emerged by way of the pleasure she derives from helping people find theirs, through fashion. 

I'm resolutely avoiding the word "hobby" here, but I'm referring to something we do without any pressure of "should", then inadvertently find that it makes us feel brilliant. It can be something spontaneous or a life-long promise-to-self (as mine was) which proves not only that it's never too late but that, in fact, some good things can only happen later than you thought. It can lead to a new career or have no goal at all (mine is, loosely, to master Great Balls of Fire and Beethoven's Moonlight Sonata, neither of which I ever intend to play anywhere but in the kitchen). It can be creative, or physical, or both, or neither. It can benefit other people. The Princess of Wales' recent Three Peaks Challenge was an impressive philanthropic version of doing something for private self-celebration. After years of putting oneself last, there comes a point when a little joy directed inward goes a very long way, and with all the other castigations channelled our way as we reach middle age, regular weight training, less booze, better sleep, stronger boundaries, this one feels indulgently self-serving while being just as good for us. 

"Learning another language could slow brain ageing by up to 13 years," Anna Bawden wrote in The Guardian recently, so it stands to reason that learning anything will make us feel good. As we undergo all the mental and emotional changes of menopause, taking on a new skill, particularly something involving coordination, memory and emotional engagement, does to our brain what the weight training we're supposed to be doing will do to our bodies, yet it feels pressure free. 

For some women a new thing gives confidence as their sense of self feels depleted in an empty nest; for others it's escapism from a never-ending mental load; and for anybody it's an opportunity to connect to that inner child we keep hearing about but haven't had time to consider during the intensive years of mothering and career building. If our identity has contracted around roles and responsibilities as a result, then learning something new, purposeless and joyful and even slightly humiliating, in midlife is an act of glorious retrieval.