There isn't an official "fastest" time but at my school (I'm 15) we have a record for almost everything you can think of so you may want to check about that.
13 seconds
21:53
it is 19.23 seconds
The fastest officially clocked pitch was by Brian Jarrell at 72 MPH.
It really depends more on the physical characteristics and health of the individuals involved and not the age or whether they are a boy or girl.
Eric Hulst 14.57.93
Lynn Gum ran mile at 3:59 when 17 years old
My 11 year old brother ran a 5:45 mile at a road race in Shorham New York
i am a 9 year old boy and i can run about 16 miles an hour. i hope you know that the second fastest kid in my class can run about 5 miles an hour.
i Ran a 11.3 in a meet 5 days ago
I doubt that any serious rigorous studies have been done on this, and further doubt there would be much difference in the average speed. That said, I suspect that in a large enough sample, the fastest boy will be faster than the fastest girl.
3 billion miles