I am sure you will find chem, physics and maths/stats very easy - you will learn basic chem and physics you learnt in high school. I think you will have a good foundation for cell & molecular bio, physiology and anatomy. I only did biology in year 11 so I found bio and physiology a bit challenging. There is a unit called Australian Health Care Systems and I think many people found it hard - you just need to do all the readings and do the assignments the way your tutor wants you to do, I found the tutorials very helpful for the assignments. The other unit you will do is Communication for Health Professionals- this one let me down because of my lack of interpersonal skills but if you hand in a solid video and essay and if your group doesn't let you down too much then a HD is quite achievable. I found that good organisation goes a long way in uni.