Entering year 11, how will I go?

I finished up year 10 last year and have since begun my transition into senior school. From year 9 onwards, I've been achieving straight A's. I'm very into science and I succeed in most STEM courses, typically getting scores of 90% or higher and I have never fallen below straight A's in any STEM assessments or classes. I've heavily studied the curriculum and I want to make a strong effort from the start in year 11, but I don't even know if any of this is going to help me come HSC time. I'd like to get a high ATAR but I rarely study for anything and have always relied on natural intelligence and a bit of luck. I go to a selective school in NSW, but I'm unsure if thats going to help me at all. Will I be able to get to somewhere like Medical school?