Levin woman Heather Robinson was happy to produce documentation to dispel any doubts about her age when asked "can I see your licence please, madam".
The 90 year old swam 90 lengths of the Levin Aquatic Centre for her birthday on Friday - no mean feat - two years after swimming 88 lengths of the poll on her 88th birthday.
"I didn't do it last year because I was ill," she said.
Mrs Robinson managed to achieve the feat in less than two hours, a good effort considering she was not as fast as she once was, by her own admission.
"I've lost my kick now so it's really just my arms, but we get there," she said.
Mrs Robinson's fit frame belied her years, and just so there were no confusion, she was happy to produce her drivers licence as proof of her age.
Originally from Palmerston North, she moved to Levin six years ago and took up membership at the town pool swimming. She had always kept herself fit, she said.
"It's just something I have always done. I've always been into sport and used to run marathons but I'm too old to run marathons now. I used to ride a bike too but I'd be pushing my luck now."
Mrs Robinson had a minor stroke earlier this year that kept her from the bike. She woke one morning and went to get out of bed and "fell felt on the floor".
Longevity was in her genes though. Her late aunty Inez Wing lived to be 107, while her great-grandmother Mrs Watt lived to be 105.
Mrs Robinson said she always ate well and as a child her father had a large vegetable garden and fruit trees in the back yard.
"I do get cross when I see very round people out there having fast food for breakfast. They should be having a proper breakfast. It's okay occasionally, but you shouldn't eat rubbish day after day," she said.
"When I was young fish and chips was a real treat."
But in what was a contradiction of sorts, Mrs Robinson said she ate chocolate, and when she was training for her marathons, she could eat as many as four chocolate bars a day.
"That's were I would get my energy," she said.