There is a reasonable body of evidence to suggest that the size of the snake and not the age is the primary determinant of breeding maturity.
Rick Shine has a table in the back of his book "Australian Snakes" which records the adult sizes of families of Australian snake from which the minimum breeding size can be determined. I took the liberty of transcribing this table for pythons on to OzPythoner site at yahoogrops.
I am not sure how this link will work for people who have a Yahoo groups ID:
http://groups.yahoo.com/group/OzPyth...portRows&tbl=2
I you have problems let me know and I will convert it to plain text and post it here.