Each year, Athletics NSW selects two competitors from each age group based on their performance at the NSW All Schools Championships, to represent NSW at the Australian All Schools Championships.
Unfortunately, due to COVID the 2021 Australian All Schools Championships were cancelled, but Athletics NSW still named a “Merit Team” of athletes who would have been selected.
See: NSW All Schools Merit Team Announced
Andres was selected in the team for the 90m hurdles and the 100m sprint:

Full criteria for selection is found here: Australian All Schools