darn good. Before you bring up FCS FCS. All the BYU QBs played FCS and other cupcakes.
If Retzlaff continues to do as poorly vs P4 as he did vs SMU, he will be benched soon. If he gets injured - he will be replaced. If he stinks it up vs Wyoming, he likely will not finish the game.
Relax. It will all sort itself out.