"Stock judging was the part of the competition that I had struggled with in the past, so I was thrilled I did so well in that component.
"That was definitely my biggest achievement of the competition."
Ms McWilliam said she was awaiting details of exactly what her ambassador's role would involve but was hopeful an overseas trip might be in the offing.
"I have spoken to previous ambassadors and they have said it changed their lives.
"Representing New Zealand at different forums internationally is a huge honour but, more than that, being able to encourage other young people to get involved in the beef industry is really inspiring to me,"she said.
Ms McWilliam and Mr Cameron own a 275ha farm in Mauriceville and are involved in the management of two other properties close by.
She said they farmed sheep and beef.