Given this information, you should be on track with an ATAR of at least 97 and up to 98.
Mathematics Extension 1 seems to be your best-performing subject, and will definitely make a positive contribution to your ATAR. Congratulations on your outstanding result!
Your position in Biology, English Advanced as well as Software Design and Development is also favourable. It is therefore likely that all of these subjects will make a positive contribution to your ATAR.
The same can be suggested regarding your performance in Chemistry and Mathematics Extension 2, although perhaps to a slightly lower extent. This means that, while these subjects are also likely to make a positive contribution to your ATAR, it may not be as significant as the rest of your subjects.
Of course, you have now finally finished your HSC. Given that they contribute the remaining 50% of your overall HSC marks, your performance in your HSC exams will be very important in determining whether your actual ATAR ends up being within this estimated range, or whether it ends up exceeding it. The latter is definitely a possible outcome, especially if your performance across your HSC exams has been of a similar or higher standard.
I hope this helps!