Unlike many children abused by adults, Tyson was able to tell her mother about the man's behaviour and testified against him in the Whanganui District Court as a 9-year-old.
"It was hard because I couldn't name the parts of my anatomy I was asked about."
The words she needed were not in her vocabulary, she told the interviewer.
Her abuser was not convicted due to lack of evidence but Tyson said the support of her "loving whanau" got her through the experience.
Tyson also made a public disclosure during the Miss World New Zealand competition in April this year and says she was inspired by a fellow contestant.
"She bravely talked about her childhood sexual abuse and I was after her so I shared my story too."
The experience inspired her to found the Brave charity this year.
Brave works to raise awareness about sexual violence affecting young people and provides tools to help those affected through community projects.
"Sexual violence affects a lot of young people and they need to know they can speak out."
Tyson told Native Affairs that being Miss World New Zealand may seem "easy and pretty" but said the role is "really, really challenging".
The title, she said, has given her a wonderful platform to speak from and as well as launching Brave she has fundraised for Annie's Lifeline - an organisation that gives scholarships to youth who are suicide survivors or have gone through mental health problems.
The charity was started by 2017 Miss World New Zealand Annie Evans.
Tyson recently held Brave workshops at Whanganui Girls College and Nga Tawa School in Marton and she plans to visit other schools in the region soon.
