Baldassarri started practising rhythmic gymnastics in Ravenna. In 2014 she moved to Fabriano, and started being trained by the olympian Julieta Cantaluppi and her mother, Bulgarian rhythmic gymnast Kristina Guiourova. In 2015 she was selected in the Italian national junior group to compete at the 2015 Rhythmic Gymnastics European Championships in Minsk, Belarus. They placed 6th in Group All-around and 5th in 5 Balls final. At the 2016 European Junior Championships Baldassarri won team bronze with Alexandra Agiurgiuculese.