I’M old at heart. Wait, before you pick up the phone to the local cardiac unit, my ventricles can still pay a half-fare, and there are chickens whose springs haven’t sprung like my own. But still, most days, I find myself with more in common with my 86-year-old neighbour than she’d likely admit – and I’m pretty convinced it’s a good thing.

Before I adopt soapbox and sandwich-board position, please believe me, I’m not suggesting that youth is wasted on the young.

Looking back along my own twisting timeline, it’s clear to see the turns at which I didn’t have the emotional breadth to cope with the intensity of opportunities before me.

I guess that’s where my affinity with those in their second youth lies. I spent too long scared to embrace enthusiasm, hiding from a go rather than having one, that now, when I fully understand what I missed, I’m determined to make the most of things – or at least a decent likeness of the most.

At 35, I’m not exactly in my dotage but I definitely recognise in myself some of those badass blue-rinse qualities that seem to take hold once the nest is emptied of responsibility

As adults, we’re oh so busy doing the work and the rest that we just never make time for the play. And I don’t mean the pint down the pub and a scratch-card type of play. I’m talking about the mud in your socks, song in your heart kind; the type that brings on a giggle before you’ve checked its paperwork’s in order.

No doubt it’s important – there’s research, but I ain’t no peer reviewer – yet still we manage to convince ourselves that wiping dead skin cells from an occasional table with a microfibre cloth is of greater value than giving our brains some air.

Lately then, in a beautiful segue, my big sister, Donna, and I dusted off our adult selves, left her kids at home – with a responsible adult, folks, it’s not the seventies – and headed off to play in a cavern system in Wales.

If you’ve ever wondered what to do with that disused slate mine out the back, you’re not alone. It just doesn’t seem right for luxury flats. Well, Zip World, the adventure destination that pooh-poohs your buttons and press-studs, turned theirs into what can only be described as the most fun you can have wearing a hairnet. Just hear me out, before you start arguing in favour of food hygiene courses, please.

Zip World is a fastening together of adventure’s biggest hitters across three separate locations around North Wales. Boasting the fastest zip line, highest power-fan tree parachute simulator and first five-seater giant swing, Zip World has a directory to back up the ego, and shows exactly what you can achieve with some imagination, plenty of rope, and an area of outstanding natural beauty.

It isn’t difficult to see why North Wales is fast becoming a magnet for the world’s adventurous sorts. But if you’re not quite 20-20 on this one yet, grab your specs and keep on reading.

Basing our trip in the surprising comfort of Surf Snowdonia’s glamping pods, we were only ever a stone’s throw from climbing, rafting and coasteering, and luckily none of their houses were glass.

With mountain, forest and sea on its very doorstep, the region surely always attracted the committed outdoor pursuiters but now, since organisations like One Planet Adventure, Ribride and Dragon Raiders Activity Park have emerged within spitting distance of each other – depending on the prowess of your salivary glands, of course – even entry-level adventurers, like Donna, are crossing to its shores.

My only sibling and I have always been fairly different. And while throughout our lives we’ve oft been called two peas in a pod, our shape and pallor are about as far as that analogy stretches. That doesn’t mean we don’t get on; burning buildings have nothing on us, particularly since her move to England meant that distance brought us closer together. But it was genuinely lovely to share a little of my new life as an adventurer with someone who spent her own childhood watching me cower from mine.

I’ll confess, on reaching the Blaenau Ffestiniog centre, it wasn’t easy to pass by the four-person zip slide, the via ferrata caverns (with steel cable as a guide) or even the deep mining tour, where I’m certain Smaug holidays, but we were there to test our fitness and tendons at one specific activity, and nothing but jumping for joy would do.

Bounce Below: a trampoline park hewn into the very earth, lit lowly as a glowworm’s nightlight, filled by the echoes of calls long since heard. Sounds special? It is. After donning hairnets and helmets and attending a safety talk that actually felt necessary, the group of excited adults began tunnelling towards entertainment – so to speak.

By the entrance, we collected little red mats, then headed into the nearest moody chamber. And the ground sank beneath our feet. In fact, the ground disappeared entirely, to be replaced by layers of stretched netting with weave open enough to allow a startling view of the depth of cave below. Pockets of webbing, as though spun by Aragog himself, from ceiling to far-away floor, housed wobbly humans of all ages, finding their feet then the spring in their step.

When finally our physiology adjusted to the new regime and, in short, we stopped falling over, we did exactly what we were there to do and just jumped. Somehow, without the bunchies and Cabbage Patch Kids, we were girls again; shouting out to each other to throw a new shape in the air or run really fast as our legs plunged into the mesh. Lying face down, side by side, we stared through the net to watch others at play, catching our breath from the laughter as much as the cardio.

Then, of course, it was time to explore, and Bounce Below has an offbeat way of transporting its players between cave levels: you climb the ladders, you gotta be prepared for the snakes.

Fear not, ophidiophobics, there’s no adder here to subtract from your fun; these particular snakes are the figurative kind, but can take you down all the same. Winding metal chutes link the various vaults, helter-skeltering you atop your red mat in their enclosed darkness to the next stop on your trampoline tour. Then there’s the biggest decision of your stress-free day: to climb back up, to slide further down or to just, you know, stay and bounce awhile.

All too quickly, our grown-up selves caught wind of the situation and sent knackered knees and gasping lungs to collect us. But even the exit to Bounce Below hits you with a clever twist, as you clamber your way up a corkscrew of netting: half-skipping, half-tripping, but fully enjoying the ride.

Once more back on the surface, we regrouped, refuelled and returned to our nearby pods, the bonds between us strengthened by another shared thread. Maybe we’ll never be kids again, maybe never know those trouble-free days of old, but surely that’s no excuse to deny ourselves those moments when life just stops and living begins.