Thomas turned senior in 2017. She made her senior international debut at the 2017 City of Jesolo Trophy where she helped the USA finish first. In July Thomas competed at the 2017 U.S. Classic. She only competed on uneven bars and balance where she placed third on each. Later in the summer Thomas competed at the 2017 U.S. National Gymnastics Championships where she placed fourth in the all-around behind Ragan Smith, Jordan Chiles, and Riley McCusker, sixth on bars, and third on beam and floor. As a result, she was named to the senior national team and invited to participate in the Worlds Team Selection Camp. After the two days of trials, Chiles and Thomas was selected as the non-traveling alternates for the 2017 Artistic Gymnastics World Championships.