Complex sentence: Aged 14, Adele discovered Etta James and Ella Fitzgerald by accident as she stumbled on the artists' CDs in the jazz section of her local music store and was struck by their appearance on the album covers.
Split into simpler sentences: Aged 14, Adele discovered Etta James and Ella Fitzgerald as she stumbled on the artists' CDs in the jazz section of her local music store. She was struck by their appearance on the album covers.