Dilmah G
As I've said before, do the subjects you like and will do well in. I don't know when you last checked the education requirements but no year 11 or 12 science subjects are required for entry, even when they were you only needed a result of 53% (for NSW). That goes for maths and english too. Anyway, all you need is a grade C in year 10 science and have to do advanced maths or whatever it's called. Just try and do well in the subjects you do and make sure you do the required maths.
ADF pilot applicants must have completed Year 12 with passes in English, Mathematics (Tertairy Entrance Level) and two other academic subjects.
ADF Pilot Selection Agency: Royal Australian Air Force