Given this information, your performance appears to be consistent with an ATAR of at least 98 and up to 99.95. I do essentially agree with Unovan's estimate, since your performance is evidently of a high standard across your subjects. This means that it is highly likely that all of your subjects will make a positive contribution to your ATAR, which will hopefully allow you to achieve your ATAR goal. An ATAR that high is therefore definitely within reach. Your chances of achieving it will depend on the 50% of your HSC marks that are yet to be determined through your HSC exams. You should aim to achieve band 6's/E4's in your HSC exams across your subjects as a minimum. The higher your HSC exam marks are from that point, the more you can maximise your ATAR and the higher your chances of reaching your specific aim.
Your favourable internal performance indicates that you have implemented, developed and maintained an effective study strategy throughout year 12. You should therefore ensure that you you continue to apply your strategy and address any areas of improvement (if applicable) as you prepare for your HSC exams.
Overall, you seem to be on track in terms of reaching your desired ATAR.
I hope this helps!