It took Jen Metzger 16 years to arrive at this moment. In that time, she founded the nonprofit organization Citizens for Local Power, chaired Rosendale’s environmental commission, was deputy town supervisor, a state senator, and a board member of the state’s cannabis control board. Early Monday afternoon on January 2, she was sworn in as county executive the top spot in Ulster County government, in front of a jubilant hometown crowd gathered before the stage in the Rosendale Theatre.