While Fushida-Hardy was skilled in maths at school - placing first equal in New Zealand in the ICAS mathematics examination when he was in Year 11 - he said the topic didn't interest him.
But external influences pushed him in that direction so he started his science degree in 2015.
"In my first maths course at the university I realised my entire understanding of what maths is, was incorrect. Since then, the more maths I'm learning the more I'm enjoying it.
"Knowledge of maths is sort of like a toolbox with which you create things, and creating things is more fun when you can do more, and to do more you just need to know more maths."
Fushida-Hardy, who attended Ngunguru School, Huanui College and completed his final year of schooling at Whangārei Boys' High School, said the idea of attending California's Stanford University came when he was doing his dissertation last year.
He had a question and found out there was someone at Stanford who had worked on something similar in the past so Fushida-Hardy emailed him some questions and ended up Skyping him to find out about the university's PhD maths programme.
Fushida-Hardy applied to about 15 schools in the United States and last monthhe found out he had been accepted into Stanford, which is near Silicon Valley.
"I spent the whole day smiling and my jaw was sore by the end of the day, and a few days afterwards," he said.
Fushida-Hardy said as part of being accepted into the programme he receives full financial support for five years, including living expenses paid, full tuition fees waived, and the university will pay for health insurance.
He will head to Stanford in early September and is "really excited."
"I'm looking at irrelevant things like the different cycling tracks they have around there.
"I like the idea of cycling," he said.
When asked what Fushida-Hardy's hobbies were, aside from maths, he said he enjoyed drawing and baking bread. But sometimes they cross.
"Recently I made a bunch of pretzels and I made them in the shape of the first 14 prime knots," he said.
Fushida-Hardy said once he has finished studying, he would love to work at a university and do research and lecture.