34. 2 Australian Junior Championships:
34.2. 1 Each State and Territory can enter a maximum of two players in the under 12, under 15 and under 18 Girls age divisions and three players in the under 18 division. Any extra spots that become available can be offered to the other States and the Junior Development Officer is to randomly allocate according to availability
34.2.2 Player's Age Groups will be determined by their age as at the 1st January of that year. The players age at that time must be less than, or equal to, the Age Group in which they are to compete. To be eligible to compete in the Under 18 Girls, girls must be a least 13 years old as at the 1st of January of that year.
34.2. 3 No player can compete in more than one Age Group in any one Championship. A Player can compete in there age group or one age group above. An Under 12 may compete in the Under 12 or Under 15 age group. An Under 15 may compete in the Under 15 or Under 18 age group.
34.2.4 Age Groups for Junior Championships are Under 12's; Under 15's, Under 18's Girls and Under 18's.
a full copy of the by-laws can be found here, http://aebf.com.au/policy/AEBF-By-Laws.pdf (December 2016)