Mary Cosby is swapping her classic 2003 Dom Perignon champagne for a casual beer, and she’s feeling seriously “regal” about the swap. The RHOSLC star hadn’t even tried a sip of the fizzy drink in her life… The Real Housewives of Salt Lake City follows the lives of wealthy residents, such as Mary Cosby. She’s never tried a beer in her life but upon her visit to the Miller Valley caves, everything changed. Mary Cosby had never tried beerDuring a cast trip on RHOSLC, Mary revealed she’d never tried beer, before getting excited over a “champagne of beers” presented to her by their tour guide at Mi…