Until 21 September 1792.
There are 54 more days until December 21, 2012.
It is the 21 of December?
North pole have no sunshine at all from September 21 until March 21. South pole have no sunshine at all from March 21 until September 21.
As today is January 11, 2010 there are 161 days until June 21, 2010.
Until September was created on 1984-09-21.
From September 21 until March 21.
In New York, you are legally considered an adult at the age of 18.
From September 21 until March 21, the shortest shadow points north from the equator. From March 21 until September 21, the shortest shadow points south from the equator.
From March 21 until September 21, maximum on June 21.
On winter season (December 20-21 until March 20-21)
Most girls have finished growing long before they reach 21. Your question did not involve most, it was "Can girls grow until 21?" The answer is yes. Some girls older than 21 have grown taller. They are the exception not the rule.