Complex sentence: Jessen's career as an activist began in 1991, when she was 14, after her adoptive mother, Dianna DePaul, told Jessen she was born to a 17-year-old girl, during a failed abortion attempt.
Split into simpler sentences: Jessen's career as an activist began in 1991, when she was 14. At that time, her adoptive mother, Dianna DePaul, told Jessen she was born to a 17-year-old girl, during a failed abortion attempt.