Hey! Seems like you are doing pretty well at school, your ranks suggest you are an average student for most subjects. Obviously your strengths are English and Music as you are pretty well ranked on those subjects. And to be doing so well in a school ranked so highly (im guessing is selective) means you're doing really well. Its good you're English is strong as that is what will definitely be counted towards your ATAR, but I am not so sure how it will scale though.
There some good Atar calculators online that you can try to use based on what marks you think you will be getting for the overall hsc