born and raised in baltimore, maryland, mackin won a four-year scholarship to the institute of notre dame before entering washington college in 1956. a year later, she transferred to the university of maryland at college park, and worked for the now defunct "free state press", a weekly paper published in suburban washington, d.c. she graduated magna cum laude in june 1960 with a b.a. degree in english and minors in economics and history. mackin was a member of alpha omicron pi women's social fraternity.