Your marks are really good, and your rank is really good as well, (Being in the top 20th percentile especially in English, means your on track), but anything can happen. From the ranks you gave me and the high marks you have received, I'm really concerned for you and your school because your school has either marked the exams really easy, or the exam was easy, or everyone is just good in English. If your school is marked easy and/or the exams were easy, this could be bad because it means your school is not preparing the students for the hardcore difficulty they will expect in the hsc. Remembering that the marks matter but the cohort progress matters more as they can be scaled down or up depending on how they go in the hsc.
If it is the case that everyone is just good in english, means that you can definitely expect a band 6, assuming you will do good in trials and get a rank in the top 10th percentile in your school, and at least an 85% in the hsc exam.
But this year is really a test year so anything can happen this year. Good luck and hope you get in the course you wanted!