The hardest thing was getting back on when she fell off, Zahnee said.
"I was scared but I did it."
While she focused on reaching her dream, her family dreamed of her life changing drastically through surgery.
Her mum, Jade Riley, said Zahnee's eyesight was failing, requiring her to wear glasses but she couldn't have the surgery she needed in New Zealand to remove the birthmark.
"She couldn't breathe properly. She had sight issues and she couldn't hold her head straight. She couldn't walk up and down stairs unaided. She'd walk into things and she would have eventually gone blind."
Around this time, Zahnee and her family raised $60,000 so she could go to New York for the life-changing surgery.
"She's been fantastic since she was given surgery. She doesn't wear glasses any more and she can ride her scooter and her bike now. It's hard to keep up with her," Mrs Riley said.
They raised the money through sausage sizzles, cake stalls, garage sales and a charity auction and dinner, among other things, all of which inspired the charity Zahnee's Cause to help other parents in the same boat, Mrs Riley said.
"We know how hard it was to raise the money. It's just lovely the tables have turned and we can give something back to the community who supported us," she said.
Project KPH has helped Zahnee publish her book.
Mrs Evans, who is the founder of Project KPH, said she had watched Zahnee thrive through riding and after surgery.
"She's a young lady coping with serious conditions but despite this she overcame those obstacles and made the most of the resources she has been provided with."
Zahnee worked with Rotorua illustrator Sue Farrell and book designer Bruce Wallace from Auckland to produce a touching tale of a little girl overcoming the odds to achieve her dream, Mrs Evans said.
Project KPH funds projects for deserving kids on a voluntary basis.
"While these kids may have different individual challenges, they all have one thing in common - a passion for making the most of life. We try to make that happen. It's a simple format with genuine Kiwi heart, it just seems to really work," she said.
Zahnee's Story is on sale for $10. Email zahneesstory@gmail.com. Rotorua Library is also selling the books of behalf of Zahnee's Cause.