She made her collegiate debut on February 9, 2017, with a pinch hit single and scored a run in a 7–1 victory over BYU.
She led the team with five triples, ranking 24th nationally and tying for ninth-most in a single season in program history.
[7] During the 2018 NCAA Division I softball tournament, she went 5-for-7 and scored five runs at the Super Regional to help the Sooners advance to the Women's College World Series.
[8] During her junior year in 2019, she played in 60 games with 52 starts and posted a .348 batting average with 48 hits, 39 RBIs and six home runs.
[9] Mendes missed the start of the 2020 season due to a torn anterior cruciate ligament (ACL).
[13] During the Norman Regional at the 2021 NCAA Division I softball tournament, Mendes broke the program record for RBIs in a postseason game with seven.
[14][15] She helped the Sooners advance to the 2021 Women's College World Series where she won the national championship and was named to the All-Tournament team.