RALPH LAUREN GIRLS: Ralph Lauren invited future style icons to his Madison Avenue office on Wednesday afternoon, hosting a runway show for his fall 2012 girls collection. Thus actresses (Kiernan Shipka of “Mad Men”), his best customers from Ralph Lauren and Saks Fifth Avenue, daughters of fashion editors and stylists and, of course, a few mommy bloggers made the scene. Front-row seats included gift bags (fringe suede bags), and the budding fashionistas clapped and gasped as each look came down the runway: Fair Isle knits, denim blazers, tweed princess coats, shearling vests, velvet holiday dresses and plenty of plaids for both day and evening.