Dont do it. If you're really keen then join a University Regiment. You get to do all the cool stuff and SAME training as the ADFA cadets but get to live a normal life at the same time.
But then everyone else at your normal Uni thinks you're a bit of a wanker. At least with ADFA everyone is in the same boat.
I have a couple of mates who did ADFA or a trade through the Army. Quite a few pros with ADFA but it is a lot of work and very regulated. It will not help that you are a lazy bastard because you can still fail ADFA and there is no-one to hold your hand and make you get things done. Better you learn self discipline before joining. All of my mates enjoyed officer training at Duntroon much better than ADFA. All of them are still in the Army a few years on after finishing their service obligations, but most are considering leaving to do something else now.
Although being paid is a benefit, I'd say get a part-time job and go to a normal Uni first (to do your degree) then decide if you want to join the army.