But if she feels like backing out, if she feels like pretending she cannot hear when the marshals call her to the gates, she only has to remember why she loves this sport so much and what it means to her on this day.
She'll remember the story her parents tell her, about how she was five and was skiing on Whakapapa - it was always Whakapapa - way too fast, way beyond her capability, as kids do.
How they told her she fell over, badly. How onlookers immediately starting calling for help up the mountain. How she got back to her feet, shook off the snow and the aches and said, "Let's go faster again".
"Mum and dad were telling me that this was such an integral moment. It sealed my passion for it," she says.
So there she is, her name has been called and she is in the starting gate. All around her there are "skiers in their GS suits. It is full on", she says.
"What if I fall? When you're older you have those realisations don't you. I was a bit scared. I wanted to go really fast and get a really good time but more important to me was to finish.
"I was standing at the start thinking, 'Oh my god, how am I going to go?' I was so nervous."
Three-two-one... Go. "You can go," the marshal emphasises, but McCardle is not the sharpest starter. After all, it's been a while. She clears the gate. She is racing.
It is, it should be noted, a perfect day for it. It is blue-sky visibility and the course is in great nick. If Amanda could choose one place in the world to be right now, it wouldn't be far from where she is, sliding down the slopes with her kids, Tim, 22, Ben, 9, and Emma, 7, in tow, husband Luke Johnson at her side, not far from dad Alan, who introduced her to the sport all those years ago.
Some of them are waiting for her at the bottom of the course and aren't much help to her right at the minute. She has to choose a line and commit to it; she has to figure this course out on her own.
"For me it was all about getting down so I did much bigger S's, much slower turns at first, but then I got into it."
She got her "mojo" back, catching her edges and taking tight lines around the gates. Her time looked like it was going to be beyond her wildest expectations when trouble struck. She became momentarily disoriented and had to stop and step up the slope to make a gate.
"I was really disappointed. I'd gained all this speed and confidence and had to stop and start again," she says.
In a race against time, and Amanda knows all about these sort of races, it was damaging. Momentum was lost. Still, her primary goal was in front of her. She was going to stay the course.
There's a video of the finish. Amanda starts as a speck and then in a series of graceful arcs, crosses the finish line. Ben and Emma, proud enough to burst, nearly bowl her over in their rush to congratulate mum.
Luke is holding the camera. There may have been tears. "It was ... it was impressive," he says, even now struggling to find the right words.
The result was in: McCardle, in bib No144, finished in a time of 90.94s. She was 79th out of 82 female competitors.
But she was, by some distance, the clear and obvious winner on the mountain that day.
Cancer is a thief and osteosarcoma is of the armed-robber variety. It doesn't just steal time, it holds you hostage in your own body.
In 2011, Amanda was struggling with neck pain that no amount of physiotherapy could help. The only way she could alleviate the pain was to loop a towel under her chin and around her head and pull it up to keep her neck straight.
A scan revealed an aggressive tumour on her spine. The prognosis was awful. The only option was urgent, life-threatening surgery.
In November that year, Amanda entered hospital, not knowing whether she would come out alive. Surgeons sliced into the left side of her neck and clamped her vertebral artery, removing the tumour as quickly as possible. She had the nerve roots of her C3, 4 and 5 vertebrae removed, leaving her permanently disabled. Part of her rhomboid muscle was grafted into her neck to replace the diseased deltoid, along with a graft from her left hip. Partially successful nerve transplants were done.
The surgery meant McCardle would never again be able to turn her head in the way we take for granted. She would never again be able to lift her left arm.
But she was alive.
Touch rugby, which she loved, was gone. Tennis was gone. A life without sport was a life too sedentary for Amanda to contemplate. "There was all this stuff I couldn't do, so I had to really dig deep and go, 'Hang on a minute, there's heaps of stuff I can do, I've just got to think outside the square'," she says. "I had to readdress a few things. There was no reason I couldn't do things, I just had to get up the courage and do it."
She and Luke bought stand-up paddleboards and the Waitemata Harbour became something of a giant rehab pool. But it was the mountain that was calling loudest.
Skiing was what she really loved. Trouble was, life had kind of got in the way in recent years.
"When you go along life's path and you think you're invincible you forget about the things that are important. You get stuck in the cycle of work and home. A diagnosis like I had was such a wake-up call for everybody. I had to follow the dream again.
"I looked at the kids and giving them what I had growing up was so important to me. I needed them to experience it."
Amanda's specialists were less keen. They knew that a bad fall could be catastrophic. "I was like, 'I'm not going to break my neck, it's full of metal,' and they were like, 'Well, actually, if you fall you will, you know ..."
Look at the x-ray. McCardle's neck is as close to man-made as a suspension bridge. There is zero cushioning between her vertebrae. The doctors' scepticism was not misplaced.
So Amanda took precautions. She took lessons, she developed a new one-pole technique. She made it all about the kids and skied within her limitations. But ski she did - as often and as long as she could.
"It's freedom," she says. "I don't know how to explain it, but it's just you and the mountain; you're in control of how far you push. It's the feeling, the mountain air. And it's the people, the spirit of friendship. When you're up the mountain everybody's happy."
A few days before Christmas last year, a lump returned. The thief was back and it was angry. The prognosis, again, was awful. Surgery was no longer an option.
So began a debilitating process that, miracle aside, will not have a happy ending.
Walking is difficult and will soon be impossible. Her strength, physical strength that is, has all but been sapped. There will be no more skiing.
That Haensli Cup race now takes on a more poignant meaning. Only a few of the hundreds on the mountain that day knew Amanda's story.
"I don't even think the people who were doing the starting gates knew," she says. "They were probably thinking, 'What's this girl doing wandering up here with one pole? She doesn't look like she moves very well; I don't think she can move her head!' "
Now you know, and what you also know is this: Amanda McCardle is a ski racer, and every run is an act of courage.
Amanda died on January 8, surrounded by family.
