Is 5'9 too short to play quarter back collegically at a D3 school?

Ask your offensive lineman. If a lot of the offensive linemen are taller or if one side is taller it will be short. You will need a relatively short offensive line. The shorter they are the shorter the reach so they will not be the greatest in protection. So actually yes it's too short. or u should start trying to get out of the pocket more often. Wish u sucess