Mitchell became age-eligible for senior international competition in 2007. At the Australian Championships, she won the gold medal on the balance beam. She then competed at the WOGA Classic in Plano, Texas and helped the Australian team win the bronze medal. Individually, Mitchell placed fourth in the all-around, tied for the silver medal on the balance beam with Katelyn Mohr, and tied for the bronze medal on the floor exercise with Alina Kozich. She competed at the World Championships alongside Daria Joura, Shona Morgan, Hollie Dykes, and Chloe Sims, and they finished eleventh in the qualification round. Mitchell qualified for the balance beam event final, where she placed fifth.