However, despite being one of two to land the internship, she's not keen to rub it in to her male colleagues too much.
"Definitely, it is very male-dominated, unfortunately. I remember when all the students signed up [to do a pre-university computer science course] we got together at the university ... and I remember getting there and thinking 'wow, there's no girls here'. There was maybe two girls out of 30 or 40 people that showed up. And since then it's kind of been the same, there's definitely more males than females in my [computer science] papers."
Miss Stewart became interested in computer science during her last year at Hamilton's Waikato Diocesan School for Girls when she completed the pre-university paper.
She works with her tutor Nilesh Kanji to try to increase awareness of computer science in young girls and the pair tutor a group called the IT Girls, made up of students from her old school.
"It would be great to see more young women in the computer labs in the future."
And her family also sees the benefits of Miss Stewart's skills.
"I'm always getting phone calls saying 'something's gone wrong, come and fix it'."