Gagnon competed internationally for the first time at the 2018 Junior World Championships in Tomaszów Mazowiecki , where he won the gold medal with the relay over 3000 m. She made her debut in the World Cup at the beginning of the 2018/19 season in Calgary . There she took 21st place over 1500 m, sixth place over 500 m and third place with the relay. In the 2019/20 season she came with two 12th places and fifth place on the 20th place in the World Cup over 1500 m. She was also third in Salt Lake City and second in Dordrecht with the season. At the Four Continents Championships in Montreal in 2020 , she won the silver medal with the relay.
Personal bests
500 m 43.144 sec. (installed on November 4, 2018 in Calgary)
1000 m 1: 30.205 min. (set up on February 2, 2019 in Dresden)
1500 m 2: 23.986 min. (installed on November 2, 2018 in Calgary)