We're off to Warragul in September - my wife has already gone, she arrived at Melbourne at 5am on Wednesday. We are married with 4 kids (aged 13-3), the way we are looking at it is at worst it will be a 2 year adventure and then we will come home - house has been Let, our cars have been sold, half our cash transferred to Oz - so we have a back-up plan if we hate it (neither of us has ever been to Oz). My wifes salary is about 60k plus commission as a podiatrist and we got NO relocation costs so are taking a much higher risk than you.
I would say a backup plan will help you move forward knowing you can return - BUT - you only live once, better to regret what you have done than what you never did.