Mary Mosser was born in McConnellsburg, Pa on June 25, 1912. Her parents names were John Wesley Mosser and Elizabeth W. Fisher. She was religiously affiliated with the Methodist Church. Mary attended McConnellsburg High School and matriculated to Dickinson College where she earned her Bachelor of Arts Degree in 1934. She was eligible to teach English Literature and Rhetoric, Health Education, French, History, and Problems of Democracy. She could also coach archery, Basketball, Dramatics, and Tennis. Upon graduation from college she stood 63 inches high, weighed 125 lbs at the age of 22. She later married William Selser and became a housewife.