In 2015 McClain was part of the Junior Olympic Program and competed at various HOPEs competitions. She competed at the 2015 HOPES Championships where she placed second on balance beam, behind Ciena Alipio, fourth in the all-around, fifth on vault, and seventh on floor exercise. In 2016 she competed the 2016 Hopes Championships where she placed first in the all-around, on vault, balance beam, and uneven bars, and second on floor exercise.
In 2017 McClain qualified for junior elite status at the Brestyans National Qualifier. She also competed at the KPAC National Qualifier and the Parkettes National Qualifier. She made her elite debut at the American Classic where she place 21st in the all-around. In late July she competed at the 2017 U.S. Classic where she placed 24th in the all-around, tying with Kayla DiCello.
2018
In early 2018 McClain competed at the Buckeye National Qualifier and International Gymnix, where she won silver on floor exercise behind Irina Alexeeva. In early July, she competed at the American Classic where she placed second in the all-around behind Kayla DiCello. Later that month she competed at the 2018 U.S. Classic where she only competed three events but won bronze on the uneven bars behind DiCello and Jordan Bowers. In August McClain competed at the 2018 U.S. National Gymnastics Championships. She finished in fifth place in the all-around and won gold on balance beam. As a result she was added to the national teamfor the first time.
2019
In February, McClain was named to the team to competed at the 2019 City of Jesolo Trophy in Italy, alongside Kayla DiCello, Ciena Alipio, and Sophia Butler. While there she helped the USA win team silver behind Russia and individually she gold in the all-around, ahead of Russian Vladislava Urazova, and on vault ahead of Russian Viktoria Listunova and teammate Alipio. She also won bronze on uneven bars, behind Urazova and Russian Elena Gerasimova and on floor exercise behind Listunova and Urazova. In June McClain competed at the Junior World Championships Trials where she placed fourth in the all-around and was named as the alternate for the inaugural Junior World Championships. In July she competed at the U.S. Classic where she won gold in the all-around, on vault, and on balance beam. In August McClain competed at the U.S. National Championships. After the first day of competition she recorded a score of 56.500 and was in first place. During the second day of competition scored a 56.100, giving her a total combined score of 112.600 which won her the silver medal in the all-around behind Kayla DiCello. McClain won gold on balance beam, silver on vault behind DiCello, and silver on uneven bars behind Olivia Greaves, and placed sixth on floor exercise. She was added to the junior national team.
2020
In March McClain was selected to compete at International Gymnix, taking place in Montreal alongside Skye Blakely, Kaliya Lincoln, and Katelyn Jong. While there she helped the USA win team gold and individually she won silver in the all-around behind Blakely and gold in all four event finals.
