When I went through I was due to start ground school 11days after my AD. I heard word of another GS a month after so I told them a fib and said I needed to give 4 weeks notice at my current job (I just wanted a final Christmas and new years free of work) They were understanding and put me into the following group.
Although I have heard of cases where groups waiting up to 6months (during the grounding and the most current group that are about to start)
If your going for SYD bases they'll push you through faster as they need experienced crew up there. I hope they push the MEL groups through because we need FA's desperately. They are even calling out CM's for FA duties.
Hope that helps
again good luck and feel free to ask as many questions as you like.