Here are the holders of the record for the youngest ever female to become a grandmaster (not to be confused with the lesser Woman Grandmaster title):

Year	Player	Country	Age
1978	Nona Gaprindashvili	Soviet Union	37 years
1984	Maia Chiburdanidze	Soviet Union	23 years
1991	Susan Polgar	Hungary	21 years
1991	Judit Polgár	Hungary	15 years, 4 months
2002	Humpy Koneru	India	15 years 1 month
2008	Hou Yifan	China	14 years, 6 months[13]

http://en.wikipedia.org/wiki/Chess_prodigy