Before Union: Garner prepped at Gibson County High School where she played four years of softball. She was a four-year starter and posted a .389 career batting average. Garner posted 36 career extra base hits, while setting school records with 32 runs scored in 2008 and 47 hits in 2007. She also holds school records for career hits (150), runs (101) and games played (136). Garner posed 25 career wins as a pitcher, including one perfect game and 190 career strikeouts. Garner was a three-time all-district first team selection, all-district second team, all-tournament and all-academic once each. She was named the team MVP in 2006 and 2009. In addition to softball, Garner was a four-year member of the basketball and cross country teams. She was an all-region performer for the basketball team's 2009 group that went 35-0 and won the state championship. Off the field, Garner was a member of FCA, Bible Club, Beta Club and Pep Club. She was named the 2009 Most Outstanding Senior by the Gibson County High School faculty.