Van Koeckhoven was born in Ghent but later moved to Zelzate. In 1991, she started swimming in a club. Her first international success was a bronze medal in the 200 m freestyle at the 1997 European Youth Olympic Festival in Lisbon. Next year she won two more bronze medals, in the 100 m and 200 m freestyle at the European Junior Swimming Championships. From 1999 she competed in regular competitions and reached the finals at the 1999 European Aquatics Championships, again in the 200 m freestyle. Her best results came in 2000 when she won two European medals and passed the Olympic selection.