[6] Kajita made her senior international debut at the 2016 WOGA Classic where she won the all-around gold medal with a total score of 55.650.

[9] She competed at the Pacific Rim Gymnastics Championships with Kiko Kuwajima, Mana Oguchi, Soyoka Hanawa, and Natsumi Hanashima, and they placed fourth behind the United States, Canada, and Australia.

[11] In the event finals, she placed eighth on the uneven bars and fourth on the floor exercise, and she won the bronze medal on the balance beam behind Ragan Smith and Raisman.

[18] She was selected to compete at the 2018 World Championships alongside Hitomi Hatakeda, Mai Murakami, Aiko Sugihara, and Asuka Teramoto.

[25] At the 2019 World Championships, the Japanese team of Kajita, Hitomi Hatakeda, Akari Matsumura, Aiko Sugihara, and Asuka Teramoto placed eleventh and qualified for the 2020 Olympic Games.