By the time she was 19 , she was demonstrating aerobatics in her own biplane at air shows .
Hoffmann was born in Gelsenkirchen , Germany , and began learning to fly at the age of 17 .
By the time Hoffmann was 19 , Hoffmann was demonstrating aerobatics in Hoffmann 's own biplane at air shows .
Hoffmann was born in Gelsenkirchen , Germany , and began learning to fly at the age of 17 .