You'll only need maths and physics if you want to join qantas.
The rest in Australia don't require it unless you're trying to get into a cadet program.
Having said that you don't want to be running a race handicapped front the start. Education is something that you can never have too much of. Get a tutor, do whatever you need to do. If you can see and end game for doing something, it's always the motivation to succeed. At least for me.