[2] As a child he would watch the evening news and write notes into a notepad about trends in the stock market.
[1] Olsen attended St Francis Xavier School, where he was a volunteer librarian, road patroller, and bell ringer.
[3] In primary school he competed with a group in an international problem-solving competition in the United States; his team won.
He was also an inaugural member of the Whangarei District Council Youth Advisory Group and helped set up a free health clinic for 12- to 18-year-olds.
[3][5] After he left high school, Olsen received an internship after a scholarship at Infometrics, a Wellington economic consultancy company which he became CEO of in 2022.