How would this work? Would I start mid-term or wait until the following year?

Okay, so, I'm an American student. An my school year ends in June. I want to go to an Australian University, and I know that the Australian school year doesn't end until December, and starts back up in either late January or early February. So, would I start mid-term (like in July, or June, or sometime around there), or would I wait until January/February? Any information you could give me would be greatly appreciated! Thanks for answering!!