Mia Tindall surprised royal watchers on Christmas Day by holding hands with Prince Louis as they walked to church.  Many were quick to ask who she was and how she was related to the third in line to the throne, so here Express.co.uk will take you through everything we know about the youngster. Mia is celebrating her 10th birthday today and is the oldest child of Zara and Mike Tindall. She was born on January 17, 2014, at Gloucestershire Royal Hospital in Gloucestershire, England. The youngster is 22nd in line to the throne, behind her mum, and is followed by her siblings Lena, five, and Lucas, two. The trio do not have royal titles because of a decision made by their grandmother, Princess Anne. She chose not to give her children Peter and Zara royal titles or HRH status. As a result, their children are not eligible for the titles. Anne said she chose not to bestow titles as it meant they would not become working royals and were free from royal obligations. Zara has …