How young is Australia?

The Australian continent began forming when the Australian Plate split from Antarctica around 125 million years ago. However, the oldest evidence of life in Australia dates back to approximately 3.5 billion years ago. So the question of how young is Australia depends on what you are measuring. Geologically, Australia is quite old, but in terms of human habitation, it is relatively young, with evidence of human settlement only going back approximately 60,000 to 80,000 years.