Kate Middleton has marked her daughter Princess Charlotte's seventh birthday with a series of sweet snaps she took herself.The Duchess of Cambridge, 40, took to the official Instagram pages for herself and husband Prince William, 39, to reveal the snaps for their legion of fans to see. In one photo, Charlotte, who turns seven on 2 May, can be seen dressed in a pair of dark navy trousers alongside a light blue jumper, which was teamed with a blue polkadot white shirt underneath.