The 17-year-old Canberra Girls Grammar School graduate will spend Christmas Day in an intensive interview for her compulsory two-year service in the Israeli military.

The daughter of Yuval Rotem, Israel's ambassador to Australia, Reut and her family have called Canberra home for nearly six years.

But earlier this month, Reut bid her friends goodbye, returning to Israel for her day-long military interview and preparing for a July entry into service.

''It's been a bit strange knowing all my friends are preparing for the holidays and university next year while I am preparing to be a soldier. I do feel different to all my friends in Canberra.'' While she was looking forward to returning to her home country and was ''very used'' to the idea of military service, Reut also felt a little apprehensive.

''Obviously no one wants to put their lives on the line, but that is the state that we are in and military service [two years for 18-year-old women and three-years for 18-year-old men] is part of our lives.'' While she achieved an ATAR of 90.25, Reut must also wait until January 7 to know her results in the International Baccalaureate, a globally recognised year 12 qualification, allowing students to compete for places at international universities.

Her two friends Rati Venkatesh and Leia Getchell also took part in the IB over years 11 and 12 at Canberra Grammar as part of the school's first full intake of IB diploma students, which began in 2011.

IB students pick up an additional subject to ACT year 12 students - equating to an additional 250 hours of school work over their final two years. It also requires a major essay, a course in philosophy, a creativity, action and service program such as music and sport, and external exams that are marked overseas. Canberra has a strong affiliation with the IB, which provides at least some continuity for diplomatic families who have senior school students. In recent years it has attracted a broader base of high-achieving local students who want an extra challenge and an international education.

Thirty years ago, Narrabundah College was the first school in Australasia to offer the course.

Telopea Park High School - which is Canberra's only bilingual, bi-national French school - introduced the French Baccalaureate in the mid-1980s and became an authorised International Baccalaureate middle school in 2008.

Red Hill Primary, North Ainslie Primary and Radford College all now offer the IB primary program, while Copland College, The Canberra College, Girls Grammar and, from next year, Canberra Grammar all offer the IB Diploma.

While Reut, as a diplomat's daughter, was an obvious candidate, Leia was also hoping for a good score in order to enrol in an American university.

Her father is the chief of mission for the International Organisation for Migration.

The Getchell family will spend Christmas Day in Boston and Leia is hoping to undertake a degree in international education or counselling after taking a gap year next year.

Meanwhile, Rati will spend Christmas in Canberra. With an ATAR of 97.8, she will need to wait until the new year to find out whether she has secured a place to study medicine at either Monash or Melbourne University.

The three women said they had loved the challenge of the IB.