Isabell was born on 21 July 1969 at Sevelen (Rhineland) and grew up at Rheinberg with her parents Heinrich and Brigitte Werth and her elder sister Claudia. She attended school from 1976-1989 and after getting her Abitur certificate she took up law studies in the winter semester of 1989. She took her final examinations in 2000 and joined the Oexmann law firm at Hamm. From late 2001 until early 2004 she was in charge of the sponsoring programme at Karstadt Warenhaus AG. In 2004 Isabell set up her own Dressage Training and Show Stable at Rheinberg/Niederrhein.