Lady Louise Windsor

Lady Louise Alice Elizabeth Mary Mountbatten-Windsor (born 8 November 2003) is the elder of the two children of Prince Edward, Duke of Edinburgh, and Sophie, Duchess of Edinburgh. Lady Louise is the youngest granddaughter of Queen Elizabeth II and Prince Philip, Duke of Edinburgh. She is thirteenth in line to the British throne, although she was eighth in line when she was born. When her younger brother, James, was born in 2007, he moved ahead of her in the line of succession.
Birth and baptism.
Lady Louise was born prematurely on 8 November 2003 at 23:32 GMT at Frimley Park Hospital in Frimley, Surrey. She was baptised in the Private Chapel of Windsor Castle on 24 April 2004 by David Conner, the Dean of Windsor. Her godparents were Lady Sarah Chatto, Lord Ivar Mountbatten, Lady Alexandra Etherington, Francesca Schwarzenbach and Rupert Elliott. Louise was the last child to wear the original royal christening gown.
Official appearances.
Lady Louise attends events such as Trooping the Colour, Christmas and family services, like the Diamond Jubilee service at Saint Paul's Cathedral. Louise was one of the bridesmaids at the wedding of Prince William and Catherine Middleton on 29 April 2011. 
Lady Louise is technically entitled to be styled as Her Royal Highness Princess Louise of Wessex. But as per her parent's wishes, she uses an aristocratic title rather than a royal one.