Amedei was born in Meldola, Emilia-Romagna on 31 January 1906. She never married, but was engaged to a man named Edoardo. Her family opposed the relationship, and Edoardo later left to fight in World War II. The two never saw each other again.
Amedei was employed by a private firm in Meldola, and later worked as a typist in Milan, to where she relocated. She retired aged 60, returning to Meldola to look after her mother with her two sisters. In her later years, she was a fan of football club A. C. Milan, and her favourite player was Gianni Rivera.
In September 2010, Amedei moved into a Meldola nursing home. Following the death of Margherita Orioli on 3 July 2015, she became Emilia-Romagna’s oldest resident. On 31 January 2019, she became the 15th person in Italy to reach the age of 113.
Amedei died in her sleep on 1 March 2019 at the age of 113 years, 29 days. At 41,302 days, she lived one day longer than Ida Frabboni, the previous longevity recordholder of Emilia-Romagna. Frabboni was also 113 years, 29 days old, but lived for 41,301 days. Amedei’s record was broken by Anna Benericetti less than two months later.