After redshirting his first year at Western Michigan in 2012, Terrell completed 133 of 251 passes for 1,602 yards with eight touchdowns and eight interceptions as a redshirt freshman in 2013.
As a 13-game starter in 2014, he completed 250 of 368 passes for 3,443 yards, 26 touchdowns, and 10 interceptions.[2]
He again started all 13 games his junior year in 2015, completing 262 of 391 for 3,522 yards, 29 touchdowns, and 9 interceptions, leading the Broncos to an 8–5 record and the program's first-ever bowl victory over Middle Tennessee in the Popeyes Bahamas Bowl.[3] Terrell completed his BBA in finance cum laude in December 2015.[1][4]
Also beginning coursework for an MBA, Terrell returned as a starter his senior year in 2016, where he threw 34 touchdowns to 4 interceptions, the best TD/INT ratio in the FBS.[4][5][6] During the season, he broke Tim Hiller's school record for career passing yards.[7] In 2016, Terrell led his Broncos to an undefeated 13–0 regular season, a Mid-American Conference championship, and a berth to the 2017 Cotton Bowl, where they lost to Wisconsin 24–16 in Terrell's final college game.