When New Zealand teenager Rutendo Shadaya was nine years old, she wanted to create the perfect birthday present for her best friend – an act of kindness that has helped land her on the front of Time magazine.

“I was very good with gift giving, and I knew she liked reading … so I was like ‘Why don’t I write a book for her?’” Shadaya tells the Guardian.

Two months later she had her fantasy novella, Rachel and the Enchanted Forest, in her hands, and, despite having previously “despised” writing, had enjoyed the process so much she wanted to push it further.

After finding out it was “unrealistic” for a girl her age to find a traditional publisher, Shadaya self-published, winning over a young local audience and going on to sell hundreds of copies.

Shadaya, now 17, has since published two more books in the series, and has just been named one of Time magazine’s girls of the year for featuring strong female leads in her work, and for using her platform to lift up other budding writers.

Shadaya, who was born in New Zealand to Zimbabwean parents and lives in Tokoroa, a rural town in the central North Island, does not know how she ended up on the magazine’s radar. It was such a surprise, she thought their first email was fake and did not immediately respond.

“What are the chances they would reach out to a 17-year-old in Tokoroa?”

She only started feeling the enormity of the recognition in the lead-up to it becoming public.

“It’s surreal,” Shadaya says. “I’m being featured with these iconic young women and I feel like its such a privilege being honoured and [seeing] my hard work paying off”.

Shadaya is one of 10 girls from around the world to feature in the magazine’s new list, and is the only girl representing Oceania.

Her series traverses themes of adventure, friendship, mental health and perseverance, as her protagonist, Rachel, overcomes challenges through pushing herself out of her comfort zone, using her magical powers for good and surrounding herself with supportive friends.

Shadaya wants “young girls to feel empowered when they read these books” and says it is “really cool to see people are interested.”

Since publishing her books, Shadaya has used her platform to encourage other young writers, including appearing at community talks and events, and more recently running a competition for writers and artists between eight and 13 years old, the winners of which will feature in a soon-to-be-released book.

Shadaya is also a keen netball player, a student volunteer, a YWCA young leader and is considering a future in dentistry alongside a writing career.

Until then, Shadaya hopes her work will inspire others around her, particularly young women and girls.

“Never let your background or age define you,” she says. “You’ll always face a lot of challenges but those challenges are built on to your journey … take that risk, you won’t regret it in the end.”

Time’s girls of the year list is the magazine’s first list to highlight girls’ achievements, and builds on its existing women of the year list.

Other entrants on the list include 13-year-old Scottish inventor, Rebecca Young, the Olympic skateboarder Coco Yoshizawa, 15, from Japan and an organ donation advocate, Naomi S DeBerry, 12, from the US.

Time senior editor Dayana Sarkisova said the girls featured in the list “prove that changing your community and inspiring those around you can send ripple effects around the globe”.

“These girls are part of a generation that’s reshaping what leadership looks like today,” she said.

“Their generation understands that change doesn’t require waiting for adulthood – it starts with seeing problems and refusing to accept them as permanent.”