Marilyn was born on March 20, 1952 as the fourth child of Howard and Mildred (Foster) Heiden in Britton, Michigan.

She was a graduate of Britton High School and attended Cleary Business College in Ypsilanti, Michigan. Marilyn worked at the Federal Prison in Milan, Michigan.

On December 1, 1972, she married Terry Welch in Dundee, Michigan and they had four children.

On October 27, 2020, Marilyn passed away at the age of 68. She was preceded in death by a daughter, Carol Welch.