Mary Jane Oster was born on March 2, 1925, in an old sod structure-built home in Greenway, South Dakota. Her maiden name was Merkel and her parents were Fred and Emma Merkel.

She had 3 brothers Harold, George and Jim. She attended Spring Creek grade school in Greenway, South Dakota and High school in Eureka, South Dakota. She attended College in Aberdeen, South Dakota for two years, earning a teacher’s degree. She then taught school for two years in Spring Creek grade school in Greenway, South Dakota.

She married Herbert Oster in July 8, 1945, and they moved to Aberdeen, South Dakota. Herbert was an insurance salesman. They had five children; Shara, Sheila, Carrol, Donna and Bryant while living in Aberdeen. They had an apartment house on 2nd Street in Aberdeen with rooms for rent for many years. Shara, Sheila and Carrol graduated from Aberdeen high school. After their graduation Herb and Mary moved with Donna and Bryant to Washington State. Where they raised Donna and Bryant and she eventually became the manager at Fred Meyer's Jewelry store working through her retirement. She was blessed with 7 grandchildren and 8 great grandchildren scattered across the United States.

After years of traveling to Arizona as snowbirds, in January 2001, Herb and Mary moved to Mesa, Arizona to The Good Life Resort, unit 3111. Herbert passed away in 3/2006 and Mary continued to live at The Good Life until her passing. She thoroughly loved The Good Life Resort and of course all the many people she met and enjoyed activities with over the years. She loved hosting card games, with snacks and a little drink of course. She looked forward to weekly poker nights and dinners out with friends. Her family thoroughly appreciates everything that the resort and friends have done for her over the years. Which included some really memorable birthday parties attended by many Good Life friends and her family members. Her life was blessed with the love of her friends and family.