Prince George, second in line to the throne, has turned 13 as he readies to follow in his father Prince William's footsteps and start at the prestigious Eton College.Kensington Palace shared a picture of the prince as his grandfather, King Charles III, and Queen Camilla wished him "happy birthday".As the eldest child of the heir to the British throne, Prince William, and Princess Catherine, George is set to succeed his father as king one day.Kensington Palace released this photo of Prince George on his 13th birthday. (Supplied)But first, he will face another daunting challenge: the terrible teens and starting at Eton boarding school in September.According to royal commentator Richard Fitzwilliams, the young prince is being "inducted into things very gradually", and as he grows older, he will increase his public appearances.The prince was born on July 22, 2013, at St Mary's Hospital in London to a global media frenzy and public celebrations. His full name is George Alexander Louis.He was quickly whisked away on his first royal tour in April 2014, when his parents visited New Zealand and Australia, where the eight-month-old was seen excitedly interacting with the wildlife.William, Kate and George initially lived in a rented farmhouse in rural Anglesey off the coast of north-west Wales.Shielded from cameras from an early age, the prince's rare public appearances as a toddler were exhaustively reported in the British media, calling him "Gorgeous George".Prince William with baby George during an official visit to Australia in 2014. (Reuters: Chris Jackson)Since then, his birthday celebrations have been kept private as well, with the family occasionally sharing official photographs."William and Catherine have done extremely well in trying to bring him up in a simple way, sort of, as normally as possible," Mr Fitzwilliams told AFP.In 2017, the family moved to an apartment in London's Kensington Palace, and George had his first day of school at a private school in south London.They later moved to their long-term home on the Windsor estate, south-west of London, where George has attended the private Lambrook School since 2022, alongside his siblings, Charlotte, 11, and Louis, the youngest at eight.Football and helicoptersHe has already been part of high-profile events, appearing alongside his family on the balcony of Buckingham Palace for the Trooping of the Colour ceremony, and helping carry the train of his grandfather's robes during Charles's coronation in 2023.Prince George alongside his sister Princess Charlotte at Trooping The Colour, the King's annual birthday parade, last month. (AP: Kirsty Wigglesworth)Unlike Louis, who has been pictured comically pulling faces at events, George has appeared to be more serious and composed in public engagements."He was a bit shy in early years", said Mr Fitzwilliams, pointing out he has been seen being "helpful to Charlotte and Louis on occasions"."If you look at him in the formal occasions, I think you can see him assuming a role reasonably easily."Beyond the royal title, Prince William has also passed on to George his love for football and his team, Aston Villa.The prince often accompanies William to Villa games, and his mother to the Wimbledon tennis tournament.Prince William and Prince George in the Royal Box watching the the Wimbledon men's singles final earlier this month. (AP: Dave Shopland/Invision)He is also said to have an interest in helicopters and could follow in the steps of his father, who has worked as an air ambulance pilot.In September, George will begin boarding at Eton, but his family will be close by in Windsor."This is where he'll be, as it were, inducted into statecraft, history," Mr Fitzwilliams said.Prince George with his family at a carol service at Westminster Abbey in December. (Reuters: Aaron Chown)Like his father and uncle Harry, George will have security at the famous secondary school, which charges more than £63,000 ($120,000) in annual fees."Now he's a teenager, Eton beckons," Mr Fitzwilliams said."Eton is the big step towards maturity."AFP