Hello there,
I would not be too concerned, others can give personal experience, but as an education person...state systems mirror each other although effetcively same (waste!) and if there needs to be specialisation it would not be until year 10 at the earliest, before the 2 year Certificate, i.e. years 11 & 12.
After high school the system is incredibly flexible due to the
http://www.aqf.edu.au , alternative pathways, mature age entry and lifelong learning via recognition of prior learning and experience. Many university programmes e.g. Medicine, do not allow direct entry from school but require life experience and other study e.g. history. This is to make sure students wish to study.
Now Australian students pay fees for post secondary (deferrable depending upon income) so I generally advise teenagers to study part time at TAFE after school (credits can be transferred to university), work part time and travel. After this they should have an idea of what they want to study, i.e. what they are prepared to pay for to get desired outcomes.
If you want specific state details get in touch.
Cheers Andrew
Cert IV WPA, B. Bus. & M. Ed.
http://www.aiec.biz