Senior National Champion in Rhythmic Gymnastics. Her mother Zsuzsi is a former Hungarian national champion in the sport.

In February 2012, the International Gymnastics Federation (FIG) awarded Zetlin a wild-card berth to compete at the 2012 Summer Games in London, England. Zetlin has been a member of the U.S. junior and senior national rhythmic gymnastics teams since 2004. She trains with longtime coach Olga Kutuzova at Capital Rhythmics in Darnestown, Maryland.

In her final year as a junior competitor, Zetlin placed second all-around at 2005 Junior U.S. National Championships in Indianapolis, Indiana, and she won the junior titles on rope, hoop, clubs and ribbon. At 2004 Junior Nationals in Nashville, Tennessee, she placed second in the all-around, rope, clubs and ribbon, as well as third in ball. In 2002, she competed in her first Junior Nationals in Cleveland, Ohio, where she placed 12th all-around.

At the 2011 Pan-American Games in Guadalajara, Mexico during October, Zetlin captured gold medals in the all-around, ball and ribbon. In September 2011, Zetlin was named to the U.S. team for the 2011 Rhythmic World Championships, which took place during September in Montpellier, France.She was the top finisher from the continent, therefore she is top contention for the wildcard for the 2012 Olympic Games. At the 2011 Rhythmic Challenge in Colorado Springs, Colorado, Zetlin won the all-around title (98.408). She also finished first in both hoop and ribbon, second in clubs, and third in ball.

At the 2010 Pan American Games in Guadalajara, Mexico, Zetlin won the all-around, rope and ball, and she placed third in ribbon. The U.S. also earned the team silver medal in rhythmic gymnastics. She captured the all-around title at the 2010 U.S. National Rhythmic Gymnastics Championships, along with first-place finishes in hoop, ball and ribbon. She earned a second-place finish in rope.

At 2009 Nationals in Dallas, Texas, Zetlin placed third in the all-around, rope, ribbon and ball, and she earned a fourth-place finish in hoop. She notched a third-place finish in the all-around at 2007 Nationals in San Jose, California, where she won ribbon, placed second in hoop and placed third in ribbon and clubs.

She is an ambassador for Best Bones Forever!, a campaign created by the Office of Women's Health that encourages girls to participate in bone-strengthening activities and eat more foods with calcium and vitamin D to build and maintain strong bones and prevent osteoporosis.