Whether whatever you are earning is enough or not, largely depends on your financial commitments , the lifestyle you have and the location of the place you want to live in.
$100,000/year is above an average salary and if you’re frugal enough, on $100,000/year, you should be able to live a good life and save some money too.
Usually if you consider living in desirable locations of cities like Melbourne and Sydney, most of your income will be consumed in the house rents. It will be a bit hard but not impossible to find places that will allow you to have a good lifestyle without burning a hole in your pocket and hence be able to make some savings too, since rent is one of the major expenses for a student living in Australia.
The property market in Australia is very buoyant. Usually in some areas of Sydney, a one bedroom apartment can be between an average of $400-$800 per week.
Depending on your preferences and tastes, eating out can vary from affordable to expensive.
There are some other expenses too on which your money depends, like buying cars, going for international vacations, buying luxury items and so on.
So it majorly depends on the choices you make for yourself.