She competed in her first major meet in 2003 when she took part in the world championships and earned a silver medal in the team event on her sixteenth birthday. She went on to win two more silver medals, on the beam and in the floor exercise. In May 2004 she moved up to the gold medal in all three events at the European Championships.
Three months later, at the Games of the XXVIII Olympiad Athens 2004, she led the Romanian team to victory in the team event. She also qualified for two apparatus finals six nights later. On the balance beam, she outscored Carly Patterson of the United States 9.787 to 9.775 to win her second gold medal. After a break of only 45 minutes, Ponor won the floor exercise final. Her margin of victory, .188 points, was the largest in the event's history.