McTaggart was born on the Gold Coast but moved to Auckland at five. She did gymnastics for 10 years, finishing second at the 2013 nationals in the allround category of her class, before a stress fracture in her back led her doctor to give her the message: "No more gymnastics for you," and she quipped that pole vault in some ways isn't that much better "but I've learnt to adapt and having a good coach helped".
She followed a friend into pole vault and hasn't looked back. Her personal best is 4.40m and rising. McCartney holds the national record at 4.80m. "I love this sport. I reckon it was just the flying in the air.
"It's got the same aerial techniques to it. It was a good transition into the sport."
The biggest lesson she's picked up in her two years in the sport is the mindset.
"Learning about what you do before competitions, after competitions, having the right feedback and coaching and probably just knowing when you are in the zone and when you've got to be switched on or off - and be serious. You can definitely tell when you're going to have a good competition by the right mindset."
McTaggart paid tribute to McCartney, although she was into the sport before McCartney shoved its profile up in lights in New Zealand.
"There's a lot more interest and people getting to know the sport. Eliza has been a big inspiration since then, being able to train with her, having the same coach, knowing I can get where she is one day and competing with her on the big stage."
Listen to McTaggart and you can hear McCartney's voice in some moments, such as putting all her success and development squarely on coach Jeremy McColl's shoulders - "I've been with him from the start. It's really great. I put it all down to him. His focus is on us as individuals, not just athletes, but as people, making sure it's fun and enjoyable."
For his part, as a former gymnast, McColl has some insight into McTaggart's first sporting activity.
He knows the way McTaggart trained in gymnastics and pointed out there are similarities, and differences between the two Macs.
"Olivia's a pretty impressive talent," he said. "She's a completely different build to Eliza, a lot shorter, but she's fast. Eliza is fast but has never done gymnastics.
"Both are hard workers, technically gifted in terms of their skill learning and both blessed with speed. As vaulters they are completely different so they have to work on different things.
"Eliza's is more about using her bigger frame, being taller. Olivia's is more about developing her athletic side. Gymnasts don't often work on their athleticism, the running and jumping."
There's a danger is pushing the talents of 18 year olds. There's much that could happen in the next few years, injuries or a change in focus for a start. But McColl likes what he's seeing.
"She's talented enough to do it," he said of whether McTaggart had the potential to follow in McCartney's footsteps. "She's quite young in years for pole vault, so it's just about riding her through that and making sure her progress is continuing."
McColl's now got an assistant for his programme, former New Zealand decathlete Brent Booker, who can run things while McColl is overseas with McCartney.
Junior pole vault kits are flying out the door. In the past three months about 60 have been sold, where 15 a year was roughly the norm.
It's not a cheap sport. Good poles cost about $1000; the type used by McCartney more. The upswing in interest is significant.
Athletics New Zealand's high performance boss Scott Goodman cautions getting too far ahead on McTaggart's prospects, given her age. Other elements such as maturation come into the equation. Athletes develop at different speeds but "there's every indication in three or four years time we'll have two world-class pole vaulters".
Olivia McTaggart
• Olivia McTaggart is following hard on the heels of New Zealand's Rio bronze medal-winning pole vaulter Eliza McCartney.
• She eclipsed McCartney's under-17 national record in Auckland late last year, clearing the bar at 4.22m, 11cm better than McCartney's previous mark and 22cm better than her own previous best.
• Her personal best now is 4.40m, which is the B standard required for next year's Commonwealth Games on the Gold Coast. The A standard is 4.58m.
• Both Macs are expected to compete in the Vertical Pursuit event on February 22 at Britomart and the Auckland track challenge four days later.