Dahlgren reached the championship podium three times in 2004, finishing third at the NCAA Women's Outdoor Track and Field Championship for the University of Georgia with a South American record of 66.12 m, taking the gold at the South American U23 Championships in Athletics and winning a bronze medal at the 2004 Ibero-American Championships. However, she did not fare as well at the 2004 Summer Olympics, managing a throw of only 59.52 m. In 2005, she improved her record to 67.07 m and bettered her previous performance at the NCAA Championships with a second-place finish. She set a championship record of 65.05 m to win the 2005 South American Championships in Athletics – her first senior title. She did not continue her momentum into the 2005 World Championships in Athletics and she threw three fouls to be eliminated in the qualifying round.