I grew up in Toowoomba, which is on the edge of the Great Dividing Range escarpment and the Lockyer Valley. It was perfect for me. My dad, Glenn, was an army medic and fitness trainer and I'd love going out walking with him, up and down all the hills. At six, I climbed my first mountain, Tabletop, a flat-topped mound a few kilometres from the city, an 11.5-kilometre hike to the top. I felt on top of the world.

PAPUA NEW GUINEA 

My dad started running Kokoda Trek trips and I begged to be allowed to come. He thought I was too young but eventually said if I went out walking three times a week for a year without fail, he'd take me. He'd set the bar deliberately high thinking I'd never manage it. But I did, so he was forced to take me. I became the youngest person ever to do the trek. I was just eight years old.

NEPAL 

I started thinking more and more about Everest, the highest, toughest mountain in the world. When I was 10, dad agreed we could trek together to Everest Base Camp. All the people and traffic in Kathmandu were a shock, as well as the snow and the cold – minus 20 degrees temperatures. But I loved everything about it. In the end, we didn't quite make it as dad got sick when we were nearly there and we had to come back. But from that point on, the idea of climbing Everest one day was always with me. 

TANZANIA

Climbing Kilimanjaro, the highest free-standing mountain in the world at 5895 metres above sea level and one of the famed Seven Summits, became another goal, but you're not allowed to climb until you're 14. So I had to wait for this one. It was an eight-day round trek and the local African porters sang us a beautiful song of welcome at the start. The setting, rainforest then alpine desert, is so different to Nepal, and so beautiful.

ARGENTINA

Climbing the highest mountain in the Americas at 6960 metres, Aconcagua in the mighty Andes, in 2014 was meant to be my last training climb before my attempt on Everest. But 160 metres below the peak, there was a white-out with a high risk of avalanches, so we weren't allowed to summit. But it prepared me well for disappointment. Later that year on Everest, an avalanche killed 16 sherpas and the mountain was closed, then in 2015, the earthquake nearly buried me alive at Everest Base Camp. But I was determined to make it and this year I finally summitted Everest at 19, and became the youngest Australian to make it.

The Girl Who Climbed Everest: the inspirational story of Alyssa Azar, Australia's youngest adventurer by Sue Williams, (Penguin $32.99) is out now. See penguin.com.au