Hi
While it is true that most airlines will prefer that you have year 12 physics and maths just do them either in year 12 or at TAFE. Year 12 level physics and math is not hard and it will be the hardest you will ever have to do as a pilot.
Once you start your training you will realise that there is not much knowledge required of either of these subjects. The physics parts are simply common sense and the math is no harder then being given some equations and being shown how to plug the numbers in. It's year 10 stuff. There is a reason you don't need a degree to be a pilot. It's because it's not that difficult.
If you want to do a university degree in aviation then you can probably be accepted without both year 12 physics and math. They will probably ask you for at least one of them though. A lot of guys I have spoken to who have done the courses did not have both and did not require amazing school results to get in. The universities running these programs are happy to have you believe me.
Flying is a great job don't get me wrong. But the really hard part is having the thick skin and determination to stay in there because as has been mentioned numerous times, it is a really hard road. If you do not have the ability to tough out year 12 level subjects you will probably not have the required fortitude to make it as a pilot. It takes character, not much else.