Most of the statements that you have listed are what you've heard from others. Attitudes, achievement etc. is subjective -what might be difficult/useful to some might not be the case for you. Important to remember that you are more likely to be successful if you choose subjects that you are interested and engaged in (and those you need for potential university prerequisites). If you aren't sure what you want to do post-schooling, understanding the most common uni prerequisites is important so you can prepare yourself. It's also worth noting that in the vast majority of cases, you are able to complete equivalent prerequisites at university and transfer after at least one semester (just might take a little longer to get to the end goal).
I am quite unsure about Physics and Human Bio as some of my older classmates told me that doing both Human Bio and Psych would be really hard.
Do what you feel is best. Not what somebody else has told you. You might actually find taking on "harder" subjects may motivate and engage you more (could also be the complete opposite, depending on how you react to situations like this!). Hopefully you have done some elective options in this space or covered these areas in Science in year 9/10 that give you at least some idea of your feelings towards these sciences?
I am thinking that I might swap out Human Bio or Physics for Modern History which is also a subject I really like and intended on picking
If History is something you really enjoy and you think you might do well in it - then maybe this is a good option for you.
But I heard it's not that useful compared to others and that it is a very content-heavy subject with a lot of memorisation.
Not useful according to who? Again, subjective. I think personally the fact you like it trumps the worries here.
Your subject choices at present are very science/maths heavy. History could be a great balance subject for you. At the same time, I would look into any scaling consequences of choosing history, especially if you're somebody who wants a high ATAR. Speaking to a careers counsellor at your school is really important in situations like these, because they will know you better than anyone here (or able to ask somebody at your school who does know you) and can give you better advice. My advice here is purely based on what you have typed without knowing you or your personal circumstances.
Good luck!
