Turning 18 traditionally comes with plenty of life-changing decisions, including which university to attend, where to work and whether to move out.
For Lady Louise Windsor, the milestone birthday comes with one very regal dilemma — whether she should become a princess. Queen Elizabeth's youngest granddaughter and the oldest child of Prince Edward and Sophie, Countess of Wessex, celebrated her 18th birthday on Monday.
The young royal, who is 16th in line for the throne, now has a very important decision to make. While it's not yet known what Lady Louise will choose, her mother explained in an interview with the Times of London last year that she has been raising her children to be practical about the lives and careers they may have as adults.
"We try to bring them up with the understanding they are very likely to have to work for a living," the Countess of Wessex said. "Hence we made the decision not to use HRH titles. They have them and can decide to use them from 18, but I think it's highly unlikely."
Lady Louise is entitled to become a princess, according to the 1917 Letters Patent, which decrees that all children of the monarch's male heirs can be a prince or princess and use the title His or Her Royal Highness.
That explains why Princess Beatrice and Princess Eugenie, who are Lady Louise's cousins, use the HRH title and are princesses. However, Princess Anne's children, Zara Tindall and Peter Phillips, do not have royal titles.
Lady Louise's brother, James, Viscount Severn, who is 13, will also be able to decide his title when he becomes an adult.
If Lady Louise decides to join her cousins and style herself as a princess, she'll be known as Her Royal Highness Princess Louise of Wessex, and could one day take on more royal responsibilities, including royal tours and patronages.