Conversation so far:
Why did Rosemary Kennedy appear at British court?
Rosemary Kennedy was presented at court to King George VI and Queen Elizabeth at Buckingham Palace during her father's service as the United States Ambassador to the United Kingdom
How did the meetingwhere Rosemary Kennedy was presented at court to King George VI and Queen Elizabeth at Buckingham Palace during her father's service as the United States Ambassador to the United Kingdom go?
At the event, Rosemary Kennedy tripped and nearly fell
How did people react to Rosemary Kennedy tripping and nearly falling at the event?
The crowd made no sign, and the King and the Queen smiled as if nothing had happened
What year was Rosemary Kennedy presented at court to King George VI and Queen Elizabeth at Buckingham Palace during her father's service as the United States Ambassador to the United Kingdom?
In 1938
What else did you find interesting about Rosemary kennedy being presented at court to King George VI and Queen Elizabeth at Buckingham Palace during her father's service as the United States Ambassador to the United Kingdom in 1938?
Rosemary Kennedy practiced the complicated royal curtsy for hours
Did Rosemary Kennedy have any other strange behaviors at the court besides practicing the complicated Royal curtsy for hours?
Rosemary Kennedy tripped and nearly fell.
Was Rosematy kennedy's  family embarrassed by her when tripped and nearly fell when she was presented at court to King George VI and Queen Elizabeth at Buckingham Palace during her father's service as the United States Ambassador to the United Kingdom?

Question: How old was she at the time?
Self-contained rewrite: How old was Rosemary Kennedy at the time she was presented at court to to King George VI and Queen Elizabeth at Buckingham Palace during her father's service as the United States Ambassador to the United Kingdom?