Sarah Jessica Parker is sharing a rare glimpse at her life as a mom of three. The "Sex and the City" alum took to Instagram to reflect on the start of the school year for her and husband Matthew Broderick's three children, 18-year-old son James and 12-year-old twin daughters Marion and Tabitha. "In the span of 7 days. One crosses the threshold into his freshman year of college. The other 2 into 7th grade," she wrote alongside photos of them on their way to class.