Charlotte lives on the North Shore but she's originally from the Hokianga - the tiny, remote village of Panguru, over five hours from Auckland. She was among 10 kids growing up on a farm. She walked 10.5km to school and back (in gumboots) - clomping a half-marathon distance over five days weekly and she'd wade through streams, bush and farmland to do so. She's used to being on her feet.
Charlotte became a teacher, instructing PE in special character schools for 30 years throughout Auckland while raising her three kids. She kept active with squash, tennis and tramping. Every time one of her kids had a birthday, they'd go away tramping.
She came to running "by default" in 1998. Her sister, Monica Tate, ran marathons and Charlotte would support her while secretly thinking "this really is silly!"
But while doing her Masters, a supervisor, renowned for wearing stunning jewellery, declared that what she wanted for her 60th birthday was "a marathon". She just had to learn how to run first. Charlotte tried to reason with her: "But we don't even really exercise" and "Can't I just buy you some jewellery instead?"
Her supervisor was determined and so they trained and ran the Rotorua Marathon. Charlotte was never registered (so this doesn't count in her official marathon tally). It was her supervisor's first and final marathon but Charlotte carried on. She loved the camaraderie while training with the Auckland YMCA Marathon Club.
"So my mate got her marathon as a birthday present and I ended up on the committee for the Auckland YMCA Marathon Club," she says.
Charlotte says she's never been a good runner. Rather she's "adjusted to running". That "adjustment" has seen her run up to 19 marathons in a year (last year). She's run in Paris, London, Zurich, Vienna and over the Great Wall of China - the latter with her son Ryan. It was memorable "seeing all that poverty" through the villages and feeling "hugely emotional" while going over the wall.
At Athens' 2500th marathon "I had a sense of all the history that I was running past. I felt it through my body". It was also "stinking hot and hard running on the road". The New York City Marathon she calls "crazy, but one of the best". She did it the same year as Herald on Sunday columnist and author Kerre McIvor. "Five bridges close down for it and millions of people come and cheer you on".
Feilding holds "one of the oldest, and smallest marathons" while she calls the Rotorua marathon "a test of survival" with its tough terrain. She's done that one 15 times.
She's completed 80 half marathons along the way but says the secret is: "Nothing special". She eats baked beans the night before a race and porridge beforehand. She doesn't take any fancy gels, fuels or electrolytes. Just "holy water" ("I'm Catholic") and some lollies for a sugar boost.
Her marathon time is usually around five hours (her fastest is 4hrs 41m in New Plymouth).
She doesn't use her watch to keep pace, or listen to music. "I can't think of anything worse. I enjoy Mother Nature. It's too beautiful out there.
"I love it out there. It's time to reflect, think about family, kids, grandkids and what I could be doing or should be doing."
She used to talk a lot during the marathons; friends would tell her: "Shut up Charlotte and save your energy." But these days she doesn't chat much "and if I don't respond to someone it's because I'm trying to breathe and keep up!"
Remarkably she's never been injured: "I see people piled up to the max on painkillers and I think, 'what's the point if you can't enjoy it?"
But she does have feet with chillblains and swollen purple toes. "They don't hurt. They're just look ugly".
Charlotte says she's looking forward to her 100th test of the 42km race and expects it will be "emotional". It will be special doing it in Auckland because that's where she did her first official marathon 15 years ago.
"I'll be ecstatic at the end. All my muscles will be aching and my bones will be tired. But it will be amen and that's that. And then I'll have a cup of tea and go dancing," she says.
But she'll keep running. Some YMCA pals are aged 80 and they still keep running in the club and "don't complain".
She will keep marathon running too because "I feel blessed to be able to finish". It doesn't matter that "I just hobble and shuffle around."