She won the gold medal at the 2007 European Cup and retained her title at the 2007 European Athletics U23 Championships with a personal best run of 9:39.40. She made her first global appearance for Poland at the 2007 World Championships in Athletics later that year, getting eliminated in the heats stage. In December, she won the individual and team bronze medals in the under-23 competition at the 2007 European Cross Country Championships. She represented Poland at the 2008 Beijing Olympics, but again failed to progress beyond the heats of the steeplechase. Having recorded a new personal best time of 9:26.93 in the heats, Kowalska reached her first global senior final at the 2009 World Championships in Athletics and finished in twelfth place. She was selected to run at the 2009 IAAF World Athletics Final and she finished in eighth.