McCartney shot to fame at the Rio Olympics last southern hemisphere winter, becoming the face of New Zealand athletics following her stunning bronze medal performance.
"Everyone doesn't go overseas to compete so it's great to help out the locals, of course, and it's nice to go to different areas to train and compete," she says via a telephone interview.
The beauty of Hawke's Bay just adds to her mission, as she strives to train with a stable of other pole vaulters from next week under coach Jeremy McColl, of Auckland, for five days.
She found gravity-defying glory at the end of a pole but her raw power has always unsuspectingly been literally under her nose - that infectious smile which has the propensity to transform a peripheral discipline into a high-octane one that exudes a modicum of sexiness and seems attainable.
"It's not one of our biggest sports but it looks like, in New Zealand, it's really going to become a big sport so it's important to support these."
McCartney describes pole vaulting as "an interesting" discipline that draws attention due to its differences from other mainstream cousins.
"It's a great sport and tests you out both mentally and physically. It's not the easiest of sports but it's a great challenge.
"It's great to see people are recognising the sport and understanding it better now."
She flirted with myriad codes as a youngster, including basketball, crosscountry, netball, squash, swimming tennis, touch rugby and water polo.
"I tried so many sports. I really loved most of them because they were all good fun and they are certainly good to try out."
Basically it dawned on McCartney, even at that age, that she could accumulate different skills to take to another sport.
Netball was her "absolute favourite".
"It was very difficult for me to give that up. I wanted to keep going but it no longer became an option because pole vault started becoming very serious as well."
Pole vaulting became a no brainer because it had a well-trodden pathway and she quickly realised she could achieve more through it than netball.
"We had the facilities and I had an amazing coach," she says of McColl, a former Oceania gold medallist who has mentored her ever since she picked up a pole at 14.
"His input is the only reason I'm into it. He is just a phenomenal coach and understands the sport so well."
McCartney describes him as a tireless coach in pursuit of taking his protégées to a high-performance level.
"He's a huge asset and that's the reason why we're all here in Auckland, really."
Plans were under way to tee up her for international meetings.
She laughs when asked if there's a possibility she could become a dual international in also trying to pursue a career as a Silver Fern.
"As well as athletics? I don't know. I don't think I'm tall enough to be a netballer," says the 1.79m tall individual who was a defender in the same team as singer Lorde during their
Takapuna Grammar School days.
The pop artist was among the scores of well wishers after she won bronze at the Rio Olympics.
The athlete's father, William McCartney, a lawyer, was into high jumping in his school days while mother Dr Donna Marshall, a central Auckland GP, was partial to gymnastics in her childhood.
"That's interesting. We didn't even pick up on that until we were two years into pole vault - that those two backgrounds are actually perfect for it, which I think is quite funny and more of a coincidence," she says but mindful that's where her genetic disposition for athletics comes from.
Nevertheless, her parents are pivotal in working as catalysts to fuel her desire to accomplish her goals.
"They are my No 1 supporters in the sport. They are just incredible and they come to all of my international competitions.
"They are always there, no matter what their position is, and I always rely on them a lot."
She religiously uses them as a sounding board to ensure she remains on the right track as she soars to the giddy heights of international stardom.
Keeping herself motivated until the 2020 Tokyo Olympics is a long haul to keep the intensity levels up but McCartney isn't fazed.
"It's a long time but it'll probably come around pretty quickly because there's a lot of competition between the 2020 Olympics with major competitions. There's always something to work towards every single year."
Leading up to mentally clearing the raised bar requires endless hours of physical training and rehearsals.
"But when you achieve a really big jump and you hit the technique perfectly that you get shot up the air by the pole it's a pretty amazing feeling.
"I guess it becomes addictive and you want to keep getting high and keep getting pushed up by the pole," she explains of an experience that almost resembles the rush one receives from extreme sport.
McCartney runs the routine through her head with precision and fervour, adopting a tunnel vision.
"I stare right down the runway and think only what I need to think about and saying what I need to get ready for that jump.
"I do it every single time, whether it be in training or competition."
McCartney's transparency, while succumbing to gravity soon after clearing that bar, is unmistakeably endearing in all its innocence and sheer joy as opposed to showboating.
"It's just exciting. It's so exciting. I just get this huge feeling of elation when you see that bar is still up there and you know that you've done it."
In the last six months, life as McCartney knows it, has shifted from its axis of the teenager going through the motions of finding a niche at the charming harbourside suburb of Devonport, Auckland, to a celebrity who has had to rapidly become familiar with the protocols of diplomacy.
"Over the last six months life is a little different now. It's just a new challenge in the sport and something new to work with but it's been amazing."
It's tough but equally rewarding and something she is trying to adapt to.
It isn't lost on her that she has become public property and that there's an unwritten clause that demands she may have to rise to other people's expectations.
"I'm trying not to be so overwhelmed with it all because everybody is so lovely and they have such great intentions and they want to talk to you and congratulate you."
In all that unochestrated chaos, McCartney actually finds a modicum of peace which, she hopes, will eventually lead back to a state of normalcy for a ritual she yearns to carry out instinctively.
How does she juggle the demands of pursuing a physiology degree with a regimented and taxing training schedule?
"With a great deal of difficulty," says the athlete who intends to follow in her mother's footsteps. "It's not too bad. This year I've only enrolled in one paper so far so it's slow progress and I can't really say I'm doing university properly."
Her academic ambitions will, no doubt, come to the fore but right now she treats it as a welcome distraction from her sporting aspirations.
"You don't want to be completely focused on sports so it's good to keep up."
Physiology fulfils her curiosity to become more in synch with the human anatomy, something she has harboured from the time she reached an age of awareness.
"I've always had interest in the human body and how it works, and medicine, so it's the best thing I can do while doing sport."
So how well does she know her own pliable body?
"Yes, it all comes into it. I occasionally do learn things at university that are very relevant to what I'm doing as an athlete and how my body is working so I do find it very interesting."
As an athlete, there's an innate sense of consciousness of her own constitution but the theory sponged from lecture theatres help depict a more succinct picture of understanding.
"When something's not going too well - the muscles or bones are feeling not the way they usually do - we're very in tune and it's very helpful understanding why and what's working inside of you."
Her meteoric rise and national acceptance hasn't rubbed off on her younger brothers, Finn, 18, and Hamish, 17.
"They are very independent and do what they want. One of them did do athletics a little bit but they're not too particularly interested in doing it with me."
However, McCartney is inspiring a generation of especially females who are running the gauntlet with poles.
"I have trained with Livvy for the past two to three years now and she's very talented so it's really exciting to see there's so much depth in pole vaulting in New Zealand," she says of Olivia McTaggart, of Kristin School.
McTaggart this year broken McCartney's national under-18 record with a 4.30m vault and equalled McCartney's NZSS height of 4.10m when at the high schools' nationals at Waitakere. Her 4.30m vault is fourth on the NZ all-time list.
That trend has spawned a group of development vaulters, including Imogen Ayris (Takapuna Grammar) and Kazaya Vos (Rangitoto College), who will also be in the classic field, and she believes it's imperative those following in her footsteps need to keep smashing records to raise the bar, as it were.
"I would love to have people jumping around the same heights because, in that way, we can hold some high-level competitions in New Zealand so I think it's a really good thing."
McCartney didn't expect to become the Piped Piper of Pole Vaulting but it amuses her that her personality has surfaced to the extent that its magnetic forces can have such a polarising effect.
"It's just opened my eyes up a little bit to people but it's not too bad a thing, it's all good."