Hi Bella
It might be a bit early to tell what your ATAR would be, but it's good to see that you've made a good strong start. There's a few factors that influence study score as well, such as how other students from different schools go, and students in your own cohort
I don't know a lot about the HSC system, being a Victorian, but I recommend that you keep it up for the rest of Year 12, and score consistently well in your exam too.
My idea is not to think about it too much, and just do your best. If you keep worrying about bands, you risk becoming anxious or too comfortable. And this is coming from someone who scored in Bottom 3% for English