Thirty-two years. That’s how long it took me to finally fly the nest and move out of my mother’s two-bedroom London flat for good. Pathetic, you might say.As someone who was always rebellious and fiercely independent, living at home was never very ‘on-brand’ for me. At the time, I felt I had little choice financially.Looking back, I was perhaps just being lazy. Certainly, lessons were learnt that I’d be keen to impart to the many young people in Britain who are doing the same – and to their parents.One in three 18 to 34-year-olds are still living at their childhood home, according to data released by the Office for National Statistics last year. That’s the equivalent of almost five million young people.It’s hard to blame them, given the state of the economy. But that’s not to say it’s always a good idea. Indeed, my story is a salutary tale for young people clinging on to life at home with their parents.Even when I was fresh out of university, almost two decades ago now, and staring down the barrel of my first proper job, my prospects were depressing.I was on a paltry salary of £18,000, working at an advertising agency in central London, and rent prices back then were already far too high in relation to those earnings.Given the choice between a flat share with strangers in the grotty outskirts of the capital for more than £1,000 a month, and staying put at my mother’s West Kensington flat on half that rent, it was no contest. Annabel Fenwick Elliott when she lived at her mother's home in West Kensington. She was charged £500 a monthThe fact that she charged me £500 a month to live in the house that was bought by my father as part of their divorce settlement was a source of contention between us. On reflection, I can see that I was being a spoilt brat. But as far as I was concerned back then, she shouldn’t have charged me to live there at all.On the other hand, the costs for parents who do choose to continue hosting their children beyond the teenage years can be crippling.Calculations for The Mail on Sunday by wealth manager Quilter found that it costs an average of £3,246 a year in food, energy and water bills to have an adult child living at home. That equates to more than £55,000 in total between the ages of 18 and 34.But apart from the costs, I urge parents to think about how staying at home might stunt an adult child’s development.It is worth noting that I didn’t spend the entirety of my formative years living at home. In my mid-twenties I moved to New York, where I spent six years inhabiting shabby apartments with an array of catastrophic roommates – a hoarder, a cocaine addict, an heiress with a personality disorder, to name but a few – and at times struggled to make rent.It was character-building, though, and I managed to achieve a lot as a result of having to yank myself up by the bootstraps; graduating from working as a waitress when I first arrived to working as a reasonably successful journalist for a national newspaper by the time I left.But after all that progress, when I eventually moved back to London just as I turned 30, my salary was cut in half. I was once again faced with the grim reality that I couldn’t afford to live by myself. I would instead have to move in with another group of randoms in a dodgy area, and have nothing left over to save for a better life.And so I opted to live with my mother again. Most of the time, we got on well and the arrangement worked. I had a small wing with my own bedroom, bathroom, living area and door out to the garden.Our dogs – two chihuahuas named Pringle and Mouse – were inseparable. She bought the groceries and did most of the cooking. In many ways, I regressed to my childhood.For the moment we’re based at a friend’s empty house in rural Essex as we prepare to settle in America, and in something of a full-circle situation, my mother is living with me to help with the kids when my husband is away workingMy love life made things awkward, however. I had a nasty habit in my twenties of having affairs with much older, often married, men. We couldn’t go to their homes, for obvious reasons, so at times they came to mine, which can’t have been comfortable for my poor mum.By my thirties I had more sensible boyfriends, but the lack of privacy remained a problem. ‘You do know,’ my mother once told me at breakfast, ‘that I can hear everything from your bedroom.’ It was mortifying.She was torn about our living situation. While she loved having her daughter close and we generally had a good time together, she could see my life was stagnating as a result of being back at home.Gone was the ambitious trailblazer who had transformed her fortunes across the Atlantic. I was back to plodding along, never having to deal with grown-up responsibilities, like managing bills and council tax, remaining for the most part single and lacking the motivation to climb the career ladder.I’ll always be grateful for the extended crash pad, but it wasn’t until my mother decided to sell the flat and downsize that my life got a much-needed jump start. I moved in with a new friend and for one glorious year before the pandemic struck, we had enormous fun.I mingled with his set and had a lively social life for the first time in years. I got a new job, which I loved. I dated, without the embarrassment of being in my thirties and still living at home.Then, most importantly of all, I met my now-husband, a German pilot. In the five years that followed, we got married, had two children and have lived in Iceland, Mauritius and Italy.For the moment we’re based at a friend’s empty house in rural Essex as we prepare to settle in America, and in something of a full-circle situation, my mother is living with me to help with the kids when my husband is away working.The other day she questioned whether, just like before, she was holding me back with her presence; given she’s fallen back into the role of cooking and caring for us.I laughed at the very absurdity of the suggestion. I couldn’t be more grateful or relieved to have her around and, on the contrary, she’s helping me move forward, this time by enabling me to work with two small children around.But what would I do in 20 years or so if my own children decided they didn’t want to move out at the end of their higher education? In all likelihood I’d be conflicted, between never wanting to let them go and pushing for them to make it on their own.Hopefully, their prospects won’t be as depressing as they are for so many Neets – those not in education, employment or training – these days.But if they do face an uphill battle, I’d let them live with us rent-free so they could build a bit of capital. There would, however, be a time limit.Most of us need some degree of discomfort in order to find the motivation to thrive. The worryingly high number of more than 24million Britons claiming benefits – who have no reason to find work – are proof of that.I might never have left that London flat had my mother not given me a little nudge. Thank goodness she finally did.