Complex sentence: Byington played in amateur shows in her school days and graduated from North High School in 1904, and shortly afterward, at age 14, became a professional actress with the Elitch Garden Stock Company.
Split into simpler sentences: Byington played in amateur shows in her school days, and graduated from North High School in 1904. Shortly afterward, at age 14, Byington became a professional actress with the Elitch Garden Stock Company.