Just a word of caution though since I'm Australian educated engineering student.

Don't take for granted that when the university tells you that it's a 4 years degree program means you can complete the degree in exactly 4 years like local universities do.

In general, a BEng paper in Australia has about 35 modules to complete.Each year you'll have like 2 semesters and a short one at the end of the year.Taking 4 subjects per semester is a really crazy thing to do and I must warn you that most of the time you'll barely get through with passes or if you're lucky, probably score in one or two of the subjects.

Unlike in local colleges where I've seen students taking over 5-6 subjects in a single semester and still make it with most subjects getting As, do not compare this with Australian universities.I'm already 23 this year and while all my friends who entered local universities with the same engineering course that I took have graduated, I still have another year to go with my degree.

You may one to ask other Australian students in this forum about how they find about the number of years they took to complete their degrees.3 subjects itself is already taxing.Four subjects per semester is the maximum that you can take although the universities won't stop you from taking a much as you like since resitting means more money.

I have a Australian friend who is taking double majors in engineering and business administration is already 26 this year and he tells me that his course is taking so long to complete.

7 subjects in one semester at UNSW?
OMG...that's like suicide man.But I think you're a very bright student to make it through.Passing all 7 subjects in one semester is already considered a feat itself.
Are you undertaking an engineering course?

For me 4-5 subjects is already almost impossible for me.If I miss these subjects, I'll have to wait for the same semester next year before I can take them.
For example subjects A,B and C are offered in Semester 1.If I didn't take say subject A or I failed it, I'll have to wait for next year's semester 1 again to take it again.So plan your modules enrolment carefully.

If you're doing it on campus, every year will cost you almost RM100k unless your family has sufficient financial backing.Apart from this the Australian Government is now considering to increase universities fees as well.