Five-year-old Prince George is coming into his own.
The future king has had a busy year, including starting a new school, welcoming a baby brother, and playing a big role in Prince Harry and Meghan Markle's royal wedding. And even though he loves being a big brother, he's ready to spread his wings.
George is "very independent now and not as interested in playing with Charlotte all the time," a source tells PEOPLE in this week's issue. "They are close, but George likes to go off and do his own thing."
You wouldn't be able to tell from his smiling fifth birthday portrait, but Prince George has also been showing off his shy side recently.
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While Princess Charlotte has been waving up a storm at recent events, George is known to be more reserved when the cameras are on him. He waved shyly and hid behind dad Prince William outside Prince Harry's wedding to Meghan Markle in May and kept his head down while visiting their baby brother, Prince Louis, at the hospital shortly after his birth.
However, George is a talkative little prince once he gets to know someone. "George takes a little while to warm up, but once he's comfortable with you, he's very chatty and charming," says the insider.
George showed off both sides of his personality on his first day of school at Thomas's Battersea in September. He posed for an official picture with his dad, Prince William, at home at Kensington Palace before leaving for the big day in which the father and son (in his perfectly pressed uniform!) held hands with big smiles on their faces.
Upon exiting the family's Range Rover when he arrived at school, George looked very serious (and a bit nervous!) as he greeted and shook hands with the head of Thomas's lower school, Helen Haslem.
However, the source says the third heir in line to the throne is "very happy" at his new school, where he is known as George Cambridge.
When Prince George is in his element, however, he's like any other rambunctious little boy. After his dad competed in a charity polo match at Beaufort Park on June 10, George charged across the lawn trailed by his three-year-old sister.
"George ran with his head up as fast as he could," says an observer. "He looked back at Charlotte once or twice but kept on going. He was not holding back. And the first thing he did when he got there was slide down the hill on his bum."
Mom Kate pointed out a group of photographers to the children as a gentle reminder, but "she let them get on with it, sliding and rolling on the grass. They were loving the great big area to play in on such a sunny day."