Matangiroa finished the swim, bike and run in an overall time of 4hr 26min 9sec. She won the rangatahi (female) division and was placed 165th overall, a fantastic result when you consider there were more than 400 individual competitors across all 20 divisions.
The Ngati Rangiwewehi and Taranaki descendant said despite finding the transition from the bike to the run the hardest part of the multisport event, she was determined to return next year, but in the longer version, the 1/2 Iron Maori.
"So I'm thinking of doing the half with my mum and my sister."
Matangiroa said one day she would like to try a full Ironman event but right now was happy to stick to the shorter versions and concentrate on her schooling and her other sporting passion, basketball.
"I have heaps of basketball on as well and right now it's all about school at the moment and just concentrating on that."
The busy youngster uses her family as inspiration when it comes to her busy work schedule.
"My dad, he is a hard worker, and because of his work I [don't] see him much. But our whanau are close, we all like to support each other. My sister Ranginui, she wasn't into any running and it's only been a year and she is fitter than me now."
Iron Maori 1/4 Ironman, held annually in Napier, has become a popular event along with the longer version the 1/2 Ironman which is being held at the same location on December 7.
Matangiroa will be there, although she won't be competing: she will be supporting her dad, who has entered the event again.
Matangiroa's results: Swim 37.32m, bike 2:07.41, run 1:20.36, overall time 4:26.09.