Don't stress too much about Year 12 results, airlines don't care, and that's from dealing with a few majors in this country. Not saying slack off just don't get upset if things don't go your way. I didn't do physics nor even finished high school but successfully been employed on a narrow body for 20 years. All down to attitude.
Also agree with the above. Get the Bob Tait BAK book now. Start getting familiar with the language.