byu website, I estimated ages for all the starters and likely back-ups. The ages are all approximate, with the two general assumptions. First, that they all graduated at age 18. Second, that they would still have been 18 for the first football game of the season if they had played college ball straight out of high school. I also did a little extra searching on google for some of the players where the information wasn't very clear on the roster. With those assumptions, I calculated an age for each.

Average age of all players listed as starters, or likely to get playing time as a backup - 21.7 years