The young Princess Elizabeth was just 10 years old when she realised her life had changed forever.
On a cold December morning after returning home from a swimming lesson she heard cries of “God Save the King!” coming from the street outside.
A footman explained her uncle Edward VII had abdicated, and her father George VI was now King. “Does that mean you’re going to be Queen now?” asked her younger sister, Princess Margaret. “Poor you!”
Thankfully, nine-year-old Prince George of Wales has learned more gradually of his own impending destiny.
But yesterday he and his sister Charlotte, seven, faced an onerous lesson in royal duty at the emotionally charged funeral of their beloved “Gan-Gan”.
And, aside from a few quite understandable tears, the young heir and spare did her proud.
Just 11 days ago the eldest children of Prince William and wife Kate were called George and Charlotte Cambridge and were excitedly starting at a new school in Windsor with brother Louis, four.
Then their great-granny died and Grandpa became King, and their lives suddenly changed too.
And yesterday they found themselves walking behind her coffin and seated in the front row of the Royal Family at their first great state event.
Their presence was a tribute to the love, sensitivity and astute parenting skills of the Prince and Princess of Wales.
Because William and Kate would not have let George and Charlotte attend unless they were convinced they could handle it.
And they did so brilliantly.
George, known to his family as PG Tips, and Charlotte, nicknamed Lottie or Mignonette (a French equivalent of “sweetie”) travelled to Westminster Abbey with Camilla, the Queen Consort, and their mother.
As the children stepped from their car, many in the waiting crowd choked up at the sight of George in his smart blue suit and black tie.
Charlotte looked equally adorable in a pleated black coat and ribboned hat which gave her a slightly Victorian air – like one of The Railway Children.
Kate rested a comforting hand on Charlotte’s back as the children were welcomed by Abbey clergy, while George looked pale but composed.
As they walked inside, Charlotte even flicked her long hair back over her shoulder, as Kate has often done.
When the coffin arrived they were joined by their father. The order of service had suggested the children would walk behind William and Kate in the coffin procession, ahead of Prince Harry and wife Meghan. But, aware of the magnitude of the occasion, the Waleses walked as a family in one line.
As the service began, George followed it carefully in his programme, while Charlotte seemed to have difficulty juggling the large booklet and fidgeted a little more.
But the odd glance and quiet word from their parents kept both children looking calm and composed. Only once did George look overwhelmed, rubbing at his right eye as the choir sang the Psalm.
At the end of the funeral they filed out behind the coffin and returned to the state Bentley with the Queen Consort and Princess of Wales.
Driving slowly through the streets at the rear of the mile-long procession, George and Charlotte gazed from the windows at the huge crowds saying their final farewells.
And then, when they reached Wellington Arch, they climbed out to join the other members of the Royal Family as the coffin was lifted off the gun carriage and placed inside the state hearse.
For a moment it all became too much for Charlotte and she briefly appeared to cry.
But after another reassuring word from her mum and brother she dried her eyes, stood up straight and even told George “You have to bow” as the coffin pulled away.
In Windsor later they took their seats in the Quire of St George’s Chapel. Charlotte sat between her mum and the Duke of Sussex, and shared a shy smile with Uncle Harry. George was on Kate’s other side with his dad.
They behaved impeccably, the picture of duty and the future of the monarchy.
Their Gan-Gan would have been bursting with pride.
