Trimble attended Cox High School in Virginia. He had a solid high school career and was ranked the 15th best shortstop prospect in the state. He chose to join James Madison following his high school career.
As a freshman with JMU, Trimble started 52 games. He slashed .276/.382/.442 (average, on base %, slugging), driving in 39 RBI with 12 doubles and 7 home runs. He earned a CAA All-Rookie Team selection for this performance.
Last season as sophomore, Trimble took a huge step forward, slashing .342/.452/.631, leading the team in slugging. He drove in a team leading 52 RBI with 22 doubles, 2 triples, and 13 home runs on the year. He earned an All-Sun Belt Second Team selection.
This year is Trimble's junior season with JMU, and he is expected to continue his success at the plate and keep improving his draft stock ahead of this year's draft.