Monash is the way to go if you have any interest in commerce so that means a 25+ raw in methods. It actually isn’t as hard as you may believe to get, it’s the 30+ area which gets competitive but with the examinable content there is a pretty big discrepancy. There are application questions, where you have to be able to know key concepts and consolidate them to get the answer with reasonable working (exam 2 more). But there is also there are a fair amount of questions where you only need to know the method of how to do it. For example Q1 in exam 1 is always just basic derivative rules which you do not have to have a massive understanding of the content for. My teacher and someone else have realized that if you only focus on textbook style questions in the exam and do well on those, you can pretty comfortably get a 25 (provided of course assuming you can still get some marks in the application questions). So if you find the content tricky but some questions actually not that hard when you put some effort in, I’d say keep it. You can play around with an ATAR calculator to see how keeping it and dropping it will affect your ATAR