When Leslie Cook enlisted in 1940, he had to lie about his age, saying he was four years older than the tender 17 years he actually was.
Now, at 101, he still hopes to go to the Anzac Day parade on Thursday despite falling in the garden and breaking his ribs.
But he still remembers the day in 1940 when he signed up for the army.
Britain was at the lowest ebb of the war. Its troops had been pushed out of mainland Europe, evacuated ignominiously from Dunkirk. Defeat and invasion surely loomed. So the teenager wanted to help.
"It was our responsibility to stand with Britain," the centenarian said in Canberra Hospital where he was recovering from broken ribs after a fall in the garden.
It was just his innate sense of what the right thing to do was: "All of this is put into you at the moment of conception. You don't have any choice, just like you have no choice whether to be tall or fat or thin.
"When I enlisted, my manager in his farewell speech to me used the word 'courage'. It would have taken more courage on my part not to have gone because it was the right thing to do."
But the age for enlistment was 21, so that's the age he said he was.
He was sent from the recruitment office at Flinders Street Station in Melbourne to the Town Hall where he was sworn in - he remembers having to swear "to faithfully serve the King for the duration of the present war and for twelve months thereafter".
There was a medical examination where he had to strip off and do exercises.
The next thing he knew he was in uniform as part of the Second Australian Imperial Force, and off to fight in the toughest theatres of war, from North Africa to Crete to the Kokoda Trail in what was then the Australian territory of Papua but occupied by the Japanese.
He fought in the desert and he fought in the jungle.
"Things were a bit difficult at times," he says.
They were a bit difficult when he and his comrades in the infantry were strafed by Messerschmitts firing 600 rounds a minute.
"If you've got six guns firing, that's a lot of bullets," he said calmly.
He said that under one attack he was saved because the man beside him said something so he turned his head and the fatal bullet missed.
He said that sometimes, German fighters flew so low that he could see the pilot's face.
There were odd incidents of black humour, like when a German pilot flew over and formed a sign to celebrate Hitler's 52nd birthday over them - as they shot back from the ground.
"The plane proceeded to climb up high and write the figure 52 in smoke in the sky."
The pilot was so scornful of the Australians' shots that he threw a toilet roll out of the German fighter's cockpit.
But that doesn't diminish the seriousness of the war.
"Every day is difficult in war," he said.
At least, he says, he wasn't a bomber pilot dropping bombs from five miles high on women and children.
"We never had to do that. The enemy was in uniform."
He regards participation in the Anzac Day commemoration in Canberra as a duty, but he is unlikely to make it this year.
A fall in the garden has kept him in Canberra Hospital, but he said he still had hope of taking part on Thursday.
Doctors and family weren't so sure. Apart from his physical frailty he remains mentally alert, reciting long war time poems faultlessly from memory.
Occasionally, his eyes moist over as he remembers an incident, like when he was being evacuated from Crete under German fire. Some comrades didn't make the barges taking soldiers off beaches. But there are no regrets.
"The whole length of the war, I never heard one person say, 'I regret that I volunteered'."
