How long does it take to become a pediatrician in Australia?

I'm trying to find out this information by Googling and it doesn't seem to be very clear and some information even seems conflicting.

I've met this person online who claims he's an Australian pediatrician at 24-years-old. Is this possible? In the U.S. you need high school, then an undergraduate degree (usually 4 years), + 4 years of medical school, + 3 years of residency training so most 24-year-olds are still in medical school and haven't even started their pediatric postgraduate training.