A key player at goal, Armstrong helped her Senior National Team to a gold medal in the 2010 FINA World Cup and the 2010 FINA World League Super Final where she garnered All Tournament Team and Top Goalkeeper honors. She earned a Silver Medal at 2008 Olympic Games in Beijing, China as starting goalkeeper. In 2007 Armstrong was named outstanding goalkeeper at the FINA World Championships and in 2008, she was named top goalkeeper at the FINA World League Super Final. Armstrong was selected to the Senior National team after attending open tryouts in May 2006, having attending University of Michigan where she is the record holder with 20 games with 10 or more saves in 2004.