Dufault's father and brother raced motorcycles in Quebec. She began riding as a four-year-old, then racing motocross and turned to go-karts as an eight-year-old. By the time that she was nine years old she had broken both arms while racing. She began racing karts nationally in Canada and the United States in several series, including the Rotax International Series, winning several karting championships. She later moved up to formula racing, including Formula BMW USA, the Skip Barber Racing Series, Formula Russell, Formula Renault, Pro Star Mazda, and Formula 3, scoring podium finishes on several occasions, and captured victories in several series. Dufault has also performed precision driving for Honda, Polaris and Yamaha, and has also extensively tested Formula cars in China and Great Britain.