It was at a California pizza joint where Mellie Wiersma, then a recent high school graduate, first got an up-close look at bartending. “[I] always admired the bartenders, their attitude, and knowledge,” she said. It took many years working a desk job, on a “normal” path, before Wiersma set out to bartend full time. Nearly two decades later, and Wiersma has helped to build and manage craft cocktail watering holes across Boston. Ever grabbed a cocktail at Bronwyn, Drink, Eastern Standard, Shore Leave, or Chickadee? Maybe you’ve chatted it up with the local bartender at the late, great dive, The Tam? She’s worked them all, as well as several spots across New York and Brooklyn.