Nigel,
You better reread the rules as stated in the kids constitution located on this website.
13. Rules Modifications (references to NFSHSA rules book):
Rule 2-1-2
The wrestling area of the mat shall be based on the age group competing, as follows:
Under 11
must have a minimum wrestling area of 15'x 15'
11 to 14
must have a minimum wrestling area of 20'x 20'
15 & 16
must have a minimum wrestling area of 24 feet square or a circular area of 28 feet in diameter