Here's the accurate math rounded to months - looks like they were pretty accurate with the BYU ones, just not the Jazz:
Rudy Gobert - 22.75
Favors -23.67
Hayward - 25
Hood - 22.42
Exum - 19.67
Average - 22.7
-----------------
Kaufusi - 21.92
Sharp - 24.75
Fischer - 22.08
Haws - 23.92
Collinsworth - 23.42
Average 23.21
So about 5 or 6 months younger.