Sarah Jessica Parker loves nothing more than being a mother, and while she prefers to keep her children out of the spotlight, she had good reason to share a rare snapshot of her girls recently.MORE: Sarah Jessica Parker reflects on sad family newsThe Sex and the City star took to Instagram to share a photo of her twin daughters Marion and Tabitha, 11, walking to school on their last day before the holidays.Both pre-teens were captured walking down their road in West Village, kitted out with