And who would bet against her, after a career that features these highlights:
•World mountain-running champion 2005 and subsequently named NZ Sportswoman of the Year
•Fifth in 2006 Commonwealth Games 3000m steeplechase
•10th in 2012 London Olympics triathlon
•2014 Glasgow Commonwealth Games triathlon
Obviously, McIlroy is no complete rookie on the bike. After turning her back on the international triathlon circuit last year, she was invited to join the Specialized Women's Racing team in Australia as a guest rider.
She has been invited back this year on a full-time basis, and will rejoin them for this week's Tour Down Under and the Cadel Evans Great Ocean Road Race later this month.
"There's a national racing series from April to October and then we have been given a few wildcards at some of the big UCI events," said McIlroy. "So they are really big races against some of the best cyclists in the world.
"I'll just take each year as it goes, get the experience this year, and that might springboard me into a few more races overseas and in Europe.
"I'll re-assess it at the end of this year and see where I'm at."
Injury has had an unfortunate influence on McIlroy's career. She failed in her bid to make the 2008 Beijing Olympics as a track athlete, which steered her towards triathlon.
But even then, her body held her back and when she tore a hamstring off the bone last year, that effectively ended her competitive triathlon aspirations.
"It was pretty disappointing and, in a sense, it forced me to make a few more decisions," said McIlroy. "I've never formally said I'd stopped doing triathlons any more, but I stopped doing ITU, had to get a job and stopped being a full-time athlete.
"But I'm still really competitive and like to ride my bike, so I decided I needed a few goals to aim for. Nationals was one of them, Taupo Challenge last month was another and it's gone from there.
"I'm actually in better shape than I thought I'd be.
I just love racing. I thought it might have subsided a little bit by now, but that competitiveness is still there."
McIlroy admits she still has a lot to learn as a cyclist, but showed in Napier, she's a quick study.
When Williams moved to close down a breakaway, McIlroy shadowed her and Buchanan, and was perfectly placed when the medals were decided.
"There's a lot that can unfold and there are so many different scenarios that can happen, you have to be on your guard and watching everyone the whole time," she said.
"If breaks go up the road, you have to decide whether to chase them or not. A lot of it is about knowing the competition and how the other girls race - you're thinking the whole way."
By contrast, the 40km bike leg of a triathlon is usually about consolidation and setting up a decisive 10km run.
McIlroy hasn't totally ruled out a return to multi-discipline racing, but that's more likely to come over longer distances than Olympic-distance triathlons.
"In my head, it's too hard to go back to ITU once you're stepping out of it for a while, just because the training required is huge." she told Ashby. "Would I do a half-ironman? Yeah, that's definitely on my bucket list.
"I would have to go in with minimal running, so I'm injury free on the start-line, which is doable.
"But I'm loving what I'm doing, my body's in one piece and I love not being sore - all the small things that make it that much more enjoyable."
