The APS doesn’t do any registration… the official registration as a psychologist (so you can legally call yourself one) requires 6 years and is done by another Board. As for registering for membership with the APS… there are different types of membership you can have. E.g.As an undergraduate, you can still be registered as a student member.
The Weighted Average Mark is the average of all final assessment results you have.. but don't worry about that, it was confusing and irrelevant.
I think your main concern now is the uncertainty of studying the Bachelor of Science? You might not think of yourself as a science-y person, but actually… the science in the B Science is the science of psychology (if you major in it)! You said earlier you didn’t like the idea of sciences like microbiology and physiology… the ‘hard’ sciences, and that’s fine! Most of the ‘science’ required comes from the psychology as I will explain now…
I’m not sure if you have you seen this file:
http://www.psy.unsw.edu.au/study/Student_Info/UG_BScBooklet_2004.pdf
You can major in psychology and minor in almost anything else, including humanities.
For B Sci, requirement #7 states 84 UOC of science. Most courses are 6 UOC (you probably already know, but one course is like a subject, and normally you do 4 courses/subjects a semester). In the 3 years, there are 14 psychology courses you can study. That actually makes 84 UOC already! However, requirement #4 says 24 UOC of science in your 1st year. That’s 4 courses. Two of them are psychology courses, that means you will only have to do 2 other science courses in your first year. Everything else you do in year 2/3 will either be psychology or courses related to your minor
There are a few courses that aren’t ‘hard’ science that can be counted as science. There’s the maths, and there’s also philosophy. Philosophy (and biology) is a really popular elective/filler in psychology degrees. Or you can try ‘History and Philosophy of Science’ courses, or ‘Food Science and Nutrition’ courses (FOOD1230).
To satisfy other requirements, you also need 24 UOC at Year 2/3 for your minor. Conveniently, in 2nd and 3rd year, after doing the psychology courses, there is 24 UOC worth of space left to study courses for your minor. However, to do 2nd year courses, you will likely need to do 1st year courses. Luckily, there’s also room for you to do that in 1st year, even after the psychology and ‘other science’. Also, to satisfy other requirements, it ends up you will need to study all General Education courses in year 1. So in the end it fits like this:
Year 1 Semester 1 courses: Psychology, ‘Science’, Minor, Gen. Ed.
Year 1 Semester 2: Psychology, ‘Science’, Minor, Gen. Ed.
Year 2 Sem 1: Psychology, psychology, psychology, minor.
Year 2 Sem 2: Psychology, psychology, minor, minor
Year 3 Sem 1: Psychology, psychology, psychology, minor.
Year 3 Sem 2: Psychology, psychology, psychology psychology.
Since there are a number of ‘science’ courses you can choose from that aren’t too science-y, and since you only have to do two of them, your concern now might be what (non-science area) you want to minor in!
If you are passionate about psychology and a career in it, then I think you are already one step ahead! There are actually a number of different opportunities and options for a career in psychology. It probably won't be easy straightforward, but even if it means going to another uni on the other side of the country, or studying until you're 30.. or whatever, to be corny, it's the journey and not just the destination! Opportunities come and go, and what is not an option now, may be an option later.
Anyway.. hope this (essay) helps! (Please check the info though.. I might be wrong)