Tröstl was born in Gmund, Lower Austria, Austria, on 26 February 1911 as one of five children. As an adult, she found work at a company called ‘Bobbin’ before working as a travel assistant in the Persil plants for 35 years. She met her future husband in the ‘Schneider’ coffeehouse in Gmund. After the birth of their son Horst, the family moved to Vienna. In her family was also a history of longevity: her father lived to age 104.

After her retirement, Tröstl moved back to her native area. She moved to a nursing home in Schrems in 2014. On her 109th birthday in 2020, she said that she was aiming for her 110th birthday, which she celebrated in 2021. About the secret to her longevity, she said: “The Lord loves me.”

Tröstl currently lives in Schrems, Lower Austria, Austria, at the age of 113. She currently is the oldest known living person in Lower Austria and has been the oldest known living person in the country overall since the death of Vienna’s Luise Pompe on 11 November 2022.