Word of advice: go for at least the first two days.
Why?
So that you are settled in, know where things are, who is who and what to do before classes start so you can hit the ground running. Once other students return and your classes start, everywhere gets busy and can be really confusing. Give yourself a break and come to orientation so that you're not as hectic when classes start and you're equipped with info and contacts that will help you throughout your course.
Some of the things you get to do during orientation that you may not be able to do/have time to do once classes start
1) meet course coordinator/lecturers
2) become familiar with course requirements, how university works and what you need to do.
2) meet other first year students
3) take a campus tour and get yourself familiar with the campus - I didn't find my way around until my 4th year when I was trained to conduct orientation tours, find your way around while others in your year and above are still wandering around confused.
4) who is here to help you? meet student services - mission engagement, counseling, disability services and academic skills unit - what do they do? what can they do for you? why are they going to be important to your success at uni?
5) find out what textbooks and readings you need and get into the co-op bookshop before the rest of the uni start lining up to get in during first to third weeks.
6) meet the Student Association - find out what they do, what social activities are on offer, clubs and groups you can join
7) take a library tour, meet the library staff, find out how a university library is different to a school library and how you can use its services to your advantage.
8) find out about community engagement at ACU and the difference it will make to your time at ACU and beyond
9) Pick up your Student ID card - get your transport concession and beat the rush
10) Take Academic Skills workshops and prepare yourself for university study
Come along, have some fun, meet your future friends