She is not long back from Thailand, where her five wins from eight matches helped the New Zealand Under 14 (junior) team qualify third in an Asia/Oceania qualifying event, booking their place for the August world championships in the Czech Republic. Stewart's selection for that was confirmed a few days ago.
"It was really good, though really hot. Our No1 had done a lot of travelling, so it was good to watch and get tips from her," says Stewart. The competition was strong, especially from Japan and China, who topped the event.
Back in Auckland, Stewart habitually plays against girls who are 17 or 18 in the Senior A1 grade, one down from the top flight of Auckland schoolgirls' tennis.
Stewart comes under the tutelage of her uncle, Troy Turnbull, a former nationally ranked player, at the Remuera club. So she beats a well-worn path between Selwyn College, her home in Meadowbank, and the Scarbro Tennis Centre, about 3km down the road from school.
She believes the young Selwyn tennis side could be very competitive were they to win promotion for next season. "We could do well. Westlake are very strong, but I'm sure we could perform."
Tennis is a primary focus sport at Selwyn, and they are looking to lay new astro-turf courts, which should help in attracting new talent and making the sport more popular.
Stewart has enjoyed the support the school has given her in allowing her to take away schoolwork on her tennis trips, and though she loves training every day, it is not overdone. There is still a good balance with her tennis, schoolwork, family and friends.
But on the court, there is a steely determination, with her double-handed backhand a feature. She tries to emulate the shot-making of her idol, the brilliant Serb Novak Djokovic, and admires his work ethic.
Originally, her older brother Cooper was the inspiration.
"He used to be really good. He used to get bigger rackets and I wanted to be like him, but he stopped," she says. Now Cooper excels in water polo at St Peter's College and is on the cusp of the New Zealand Schools squad in that sport.
Singles is Stewart's preference, but she still enjoys doubles.
"It was really cool winning the doubles with Zara because I hadn't played with her before. I like singles. I can concentrate more, but I enjoy the doubles aspect, like firing your partner up, and it's nice to win with someone."
Since 2012, her tennis CV shows a stack of achievements in age grades, but she points to her experience in Thailand as the top of the list, because of the international competition.
