Complex sentence: Following Lillie's death in September 1913, she enrolled in the Wright Flying School in Dayton, where she learned both flying and airplane construction, and in March 1914 she became the school's first female graduate.
Split into simpler sentences: Following Lillie's death in September 1913, she enrolled in the Wright Flying School in Dayton. There she learned both flying and airplane construction and in March 1914 became the school's first female graduate.