Christie Brinkley is staying young and soaking up the sun! The 68-year-old model shared a stunning Instagram shot of herself on the Caribbean beach on Sunday, taking in the bright sun at a gorgeous tropical locale. Christie was photographed walking along the beach and taking a small dip in the ocean, showing off her stunning physique in a baby blue-colored one piece swimsuit. “Grateful!” the mom-of-three captioned the post, as she also featured a sun hat hanging around her neck and kept the rays at bay with sunglasses.