 Mitchell graduated from Wellesley College in 1972 with a Bachelor of Science degree in astronomy and received her Master of Arts degree in Early Childhood Education Leadership from the Bank Street College of Education in 1988.She is also the recipient of a Certificate in Early Childhood Leadership Development (1995) from the University of North Carolina at Chapel Hill.Mitchell began her professional career as a teacher-director of a child care center in a low-income house development in Cambridge, Massachusetts.