She played college softball for the Florida Gators from 2016 to 2019, earning All-American honors during her tenure with the team.
Born and raised in Marietta, Georgia, Barnhill tried out many sports in her youth, beginning with soccer.
[10] She was also named a National Fastpitch Coaches Association (NFCA) and Louisville Slugger High School All-American.
[10] She finished her freshman season with a 15–1 record, as well as 167 strikeouts and an opponents' batting average of .140 in 108.1 innings pitched.
[20] Entering her senior year, Barnhill became a founding member of UF's Alpha Phi chapter.
[22] The Gators defeated the Alabama Crimson Tide to win their second consecutive SEC tournament championship.
[23] The Gators suffered a 15–3 defeat to Alabama and the game marked one of Barnhill's shortest outings in her career.
[24] At the end of her Gators softball career, she held school records in ERA (0.92), opponent batting average (.124), and strikeouts (1,208).
[26] On April 16, 2019, the Chicago Bandits of the National Pro Fastpitch league selected Barnhill first overall in the 2019 NPF Draft.
Barnhill later played professionally overseas in Italy, the Netherlands, New Zealand, Taiwan, Colombia, and Australia.
[1] At the 2016 WBSC Women's Softball World Championship, Barnhill was a gold medalist, pitching four innings with four strikeouts and two hits allowed.
[1] Barnhill again represented the women's national softball team during their second consecutive gold medal run in 2018.