"It's such a cool sport to be able to turn up to race, and have your grandchildren and children racing on the same day too. I don't know many sports where that's possible at the same event.
"For me it's almost a compliment to say it's a kids' sport."
Quin's life has had obstacles, but also significant peaks, none more so than winning the world crown in France in 2004.
"It was amazing. It was the dream to become a world champion and for us that's the pinnacle event because there's no Olympic downhill. That was always the goal."
Quin, 36 and blessed with a relentlessly upbeat personality, has had her share of spills. She has broken her "fair share" of wrists and then there's the "stupid ones", breaking fingers or shoulder blades. "If I hit the ground and something hurt, sure enough I'd have broken it."
There were also what she refers to as "a couple of pretty big biffos". That'll be the two broken necks, one at Auckland velodrome in 2002 - no matter, she won the world title 18 months later - and in Nelson four years later.
"I ended up going over the bars awkwardly and broke my C2, which is a bit dodgy.
"But I've been fairly lucky in a lot of ways. No broken legs, ankles or knees, nothing like that."
She packed in mountain biking in 2007; other priorities were looming.
Her first child, Jay, was born the following year. He'll turn 5 on the day Quin races next week. Indigo is 7 months old.
Home life has had challenges too.
Her husband, Niki Urwin, was a leading motocross rider, a winner of six New Zealand titles. Competing in the Australian four stroke nationals in 2002, he crashed, broke his back and was left a paraplegic.
Within a year he had his karting competition licence and three years ago became the only paraplegic to have competed at the world championships, in Italy. Quin talks of the inspiration she gets from her husband.
On discovering the worlds were a couple of hours up the road from home in Tauranga, it was too good a chance to miss. The competitive juices were flowing - "I had to find a way to man up and go and do it" - even though she'd had little training time leading up to the nationals in Cambridge last Easter, because of giving birth to her daughter.
"I thought it was probably doable," she quipped of the pregnancy, birth and soon-to-follow world champs.
Quin, for whom a bike of some sort has never been far from her life, works on the Kids Can Ride programme in Tauranga, teaching youngsters to ride safely. A working mother, she calls herself, and doesn't strike you as someone who'd sit about all day twiddling her thumbs.
As for next week, the woman who describes herself in her competitive mountain bike days as "a woman possessed" hopes to make her final.
"That would be really cool. Anything else would be a bonus."
The family will be there. She'll probably have a thought back to her formative years.
Her big ambition back then was getting to a BMX world champs. She did get to the top of the world, albeit in a different discipline.
But "to come back and do a worlds in my own country fulfils a childhood dream".
