The wedding was set for November 20, 1947

[LouisFerdinand]

Princess Elizabeth's wedding was set for November 20, 1947.     
Citing the coal shortage and the country's economic collapse, King George VI suggested a quiet ceremony at St. George's Chapel in Windsor to minimize the expense of pomp and ceremony.     
Elizabeth and her mother insisted on a big wedding. The King suggested June of next year when, he said, the weather would be warmer.   
Princess Elizabeth said she was getting married in November.

[TLLK]

And the bride and her mother overruled the King on this and likely other occasions.  :D

[Curryong]

Absolutely, TLLK!  :D I think it's often forgotten that Elizabeth was very very sure of her feelings for Philip from an early age, and she had been waiting for quite a while. I think her parents did have some misgivings early on because she had met so few males really. In the normal course of events she would have come 'out' at 18 and gone to lots of balls and house parties. That was all disrupted, rather as her mother's teens had been, by war.

However, it is well known that George VI didn't want the family circle broken so soon and he had asked Elizabeth to wait until after the South African tour before becoming engaged.