Hey Fabio,
I am also in Aus and am also 22. First of all I'm going to assume that you have slaved and saved $45k and tucked it away in your bank account so CONGRATULATIONS.
A lot of people would have blown it on a car or some other large purchase by now.
As a little preface, I'll tell you that I'm working as a tax accountant so I am exposed to a lot of the financial decisions people have made and are making at the moment.
There are 2 ways you can look at things at the moment:
1) Interest rates are low. This means you could borrow more than you normally could and invest in some nice property. We need to look at why you are buying the property. Are you hoping that it will increase in value and you will sell it in a few years for a nice profit? Are you buying it to rent now and eventually move into? Ideally if you are looking to get a loan, you should consider not just paying the interest. You should be paying interest and the actual loan amount (principal). The low interest rates at the moment mean you could be able to afford the interest and also pay down the actual loan itself. Depending on your salary at the moment, this could be a smart move. If interest rates started to rise in the future, you would have paid down some of the original loan amount and the increase in interest rates would hopefully not affect you too badly.
There is of course a second way to look at this:
2) Interest rates ARE low.
Everyone can borrow more money than normal at the moment, based on their salaries, and so the price of property is actually increasing.
As a result, some property is selling for prices above what it's actually worth.
This means that if you bought now, and interest rates rise in the future, you would be stuck with a loan that is greater than the value you would get from selling your property.
This is a really brief summary - and more of a brain fart (it's late and I'm kind of just unloading a little). Send me a message if you'd like to know more.
Ideally you would find a good accountant, who is well versed in all of this, develop a good relationship with them so that they can guide you through with their advice and experience.