Agnelli comes from Caspoggio in Valtellina . At the age of 15 she took part in FIS races from November 2007 . She made her debut in the European Cup in January 2010 in Caspoggio. The entire 2010/11 season was canceled due to injury. In February 2012 she finished in the points for the first time in the European Cup. A month later she won the silver medal in the team competition at the Junior World Championship 2012 in Roccaraso . In December 2012, she achieved her first victory in an FIS race, and in March 2013 she became Italian junior slalom champion.
On November 22, 2013, Agnelli achieved a European Cup podium for the first time with third place in the giant slalom in Levi . Four weeks later, on December 17, 2013, she made her first appearance in the World Cup ; while she retired in the slalom of Courchevel . During the 2013/14 season, she achieved four more European Cup podium places in the giant slalom discipline, including a victory on March 14, 2014 in Soldeu . As a result, she took second place in the discipline ranking. Agnelli won her first World Cup points on March 7, 2014 with 21st place in the giant slalom in Åre . Her best World Cup result so far is 17th place in the giant slalom in Kühtai on December 28, 2014.