Sixty years ago George VI died of his lung cancer at Sandringham Palace out in Kenya the young Princess didn't know for some hours. She returned by plane a week after he had seen her off. To mark that Diamond Jubilee here is how, the event was reported.
The woman who replaced him of course was only heiress presumptive at the time she was born. Her Uncle was next in line to the throne and even when he didn't and her father became King if she were to have a brother he would have overtaken her in the line of succession. Of course we all know that before her uncle could marry, he abdicated his throne because the woman he loved, a double divorcee wasn't the right person for the establishment. Her only other sibling was a little sister. Thus it was that Elizabeth Alexandra Mary succeeded her father, the reluctant King George VI, as Elizabeth II.
Here is some footage of her coronation the following year.
The public perception of the Queen has often been one of seriousness of purpose, but of course over her 85 years and 60 years as Monarch there have been occasional glimpses of some of her lighter side.