She was one of 12 students invited to Wellington, where the list of contenders was narrowed down to four.
"In Wellington they did a similar test to what is going to be done at the Olympiad," she said.
There will be a four-hour written test and a multi-choice test where they see pictures of countries or locations and have to choose where it is from.
Her fellow New Zealand teammates are from Auckland, Christchurch and Kerikeri.
The geography enthusiast is looking forward to exploring Serbia and learning about other places through her studies.
"[Geography] is just relevant to what is actually happening in the world, you learn about what is happening and how people are trying to solve things like climate change and urban problems."
Sarah will need to raise about $4500 for her trip, but has not yet decided what sort of fundraising ventures she will be doing.
