I'd suggest you take an extended holiday there and get a feel for the place first.
I genuinely didn't like Australia as much as people made out I should. The UK for all its faults has a lot going for it. Australia isn't simply the UK in the sun; they are a very different and often unrefined culture, often blunt to the point of rudeness, self-centred and simplistic in the outlook amongst other things.
I found for example, that most Australians simply do not get or understand dead-pan humour; they just think that you're moaning. And whilst moaning is a British tradition, the Australians don't really seem to have time for it.
The sunshine can be a lot of fun, but the weird concrete-cum-wild-west architecture and lack of substantial history is something I found tedious and boring. Everything is a very long way apart and every other animal there can seemingly kill you.
It's a big, big, big place and you end up aware of just how far away from the UK you are. At times, it may as well seem that Blighty is on another planet.
Australia is essentially an unrefined, bland, isolated albeit sunny and expensive imitation of the UK and US. I often felt that Australia was trapped 20 years behind the rest of the Western word.
That said, I met some incredibly friendly, kind, and spirited people and the landscape can be breathtakingly beautiful at times. It does have a lot going for it.
It seems to me that people never really seem to mention the drawbacks. I think it would be very wise for you to try and spend a substantial period of time there and see if it works for you before committing to anything long-term. It's a great place to visit, but I don't think I'd personally want to live there.