During her athletic career at Marian University (Indiana) Monahan was a four-year starter. She finished each season among the top 10 NAIA leaders in save percentage. Monahan was named to the All-Independent Conference Second Team her sophomore year and was listed on the Mid-South Conference academic team.

During the 2019 season, Monahan was awarded Defensive Player of the Week honors for two weeks and was named NAIA Defensive Player of the Week. Throughout her junior year, she aided in leading the team to their first national tournament appearance.

Monahan graduated from Marian in May 2020 with a degree in communication and a minor in psychology.