it's proof to you.
By that logic, proof that Australia even exists is only proof to people who've been there. I've only ever seen pictures and videos; I've met a couple of people who claim to have been there, or claimed to have lived there; but that's only proof to them; right?
There is a difference between evidence and proof and the level of evidence needed to be regarded as proof is subjective. Actually to a certain degree - I guess if we want to be literal we would have to say that there is a level of evidence needed to accept a theory as true - we can't usually "prove" that theory. For example the worlds leading climate change scientists all believe that climate change is occuring as a direct result of humans actions. However only something like 46% of journalists who report on climate change actually believe it is occuring because of our actions - and to further that point - there are plenty of regular people who choose to believe the journalists instead of the experts.
You've seen photos, tv shows and met people who say they've been to Australia and that is very convincing. In fact you'd have to say that it dispels all reasonable doubt that Australia exists but does that make it proof?
Generally proof would require you to know without doubt - not know without reasonable doubt. There's a slight but significant difference. Is it theoretically possible that those pictures are fake and that the videos were fake and the people are lieing to you? There's obviously no reason to think that that is the case, but is it theoretically possible? If so, and I think it is, then you don't have proof - just strong enough evidence that you should be convinced of Australia's existence. A miniscule amount of faith is still required to believe that Australia is real.
I, on the other hand, was born in Australia and have spent my entire life here (disregarding a holiday to Asia). I have to accept that as long as we make the assumption that our perceptions are mainly true, Australia exists. It's not absolute proof, and indeed science doesn't allow for absolute proof, but the assumption we have to make is the most basic assumption we can make. Without that assumption everthing is false. Now some religions and philosophies do say that what we see as the real world doesn't actually exist and although people who haven't studied philosophy in any great detail often ridicule that sentiment, it is well argued and theoretically possible. In Western philosophy however, we are more materalistic and we assume that what we sense is real (or based on some physical reality) (sense as in see, touch, taste, hear and smell).
Proof is a complicated subject and I am certainly not in a position to come close to covering it. That would take years and years of philosophical study and thought and even then I don't think definitive answers could be constructed.