In her first year with the Lady Hornets after transferring from Colorado State.

At Colorado State 2018-19
She was the second leading scorer and rebounder for Colorado State in 2018-19 at 10.7 points and 4.8 rebounds per game. She made 67 three-pointers in 30 games to rank third in the Mountain West in three-point field goals per game. She started all 30 games for the Rams and averaged 38.1 minutes per game to rank sixth in NCAA Division I.

At Seward County 2016-18
Mounsey was a two-time NJCAA First-Team All-American for Coach Wynn at Seward CC. She averaged 18.9 points, 4.6 rebounds and 2.7 steals per game as a sophomore with 113 made three-pointers in 2017-18. Her 143 three-point field goals made as a freshman were the most of any women's basketball player in the nation - NCAA, NAIA or NJCAA - that year. She averaged averaged 19.9 points, 5.5 rebounds and 3.0 assists per game for the 2016-17 season.

High School
She was a four-time district MVP and an all-state athlete in basketball at Follett HS. She was also a top athlete in track & field and softball. She was a two-time state champion in throwing events and was a four-time all-district athlete in softball.