Wilhelm, who was born in Sölden, skied for the first time when she was 2½ years old. In 1991 after several junior races she was accepted into the ski school in Neustift. In 1995, after completing secondary school, she went to the ski school in Stams . In July 2000 Wilhelm graduated from high school. After graduating from high school, she was with the armed forces for six weeks of basic training.
As an army athlete, she was world champion in the Super-G at the Junior World Championship in Québec in 2000 . The following year, at the 2001 World Junior Championships in Verbier , she was once again world champion in Super-G. She made her debut in the World Cup in 2000 at the World Cup finals in Bormio , where she reached 20th place. In 2001 Wilhelm was accepted into the A-team of the ÖSV after very good performances in the European Cup . Since then she has mainly competed in the World Cup. Her best result was fourth place in December 2006 at the Super-G in Lake Louise .