Upon returning to Tairua, he set his sights firmly on joining the brigade as soon as possible, even completing his medical tests in the weeks prior to his birthday.
Now Billy is right beside his fellow volunteers whenever there is a callout - even during school hours.
"If the siren calls, I run out to the side of the road with my bag over my back and my pager in my hand, and if someone is driving past I'll wave them down and ask them to drive me to the station," says Billy.
"The local community are really grateful. They're more than happy to drive me. I have a good chat to them on the way and I tell them 'just stick to the speed limit', I don't want anyone getting hurt!
"My teachers all know that if the siren goes I'm going to stand up and run out. I haven't had someone turn me down yet."
Billy has to make sacrifices to volunteer, such as letting the station know if he's away from town and being available to help whatever the time of day or night, weather and type of emergency.
Fire Chief Chris New says Billy attends everything from fatal car accidents to installing fire alarms into homes on his weekends and after school, and never turns anything down.
"At an emergency we don't look around to see who it is we just look around for a hat, and the stripes on the hat tell you how senior they are. Billy is waiting for his qualified firefighter ranking to give him a red stripe, and he's working toward that now," Mr New says.
"He never knocks back a job; we had a fatal accident out of town not long ago and Billy was right in there with us and it didn't faze him."
It's not the adrenaline or any sense of glory that motivates Billy, but being on a career path that he hopes will end with a job in Auckland as a paid firefighter.
"I like helping people. It's the personal satisfaction that you get after a job," he says.
"I like how it's structured because you are always learning something different and never one callout is the same. I put into it what I get out of it, and I feel the fire service will help me develop and grow."
Billy approached fellow volunteer and mentor Mike King about a campaign he'd seen in Hamilton to install fire alarms in the homes of elderly.
With Mike's support and training, the pair began installing alarms throughout Tairua. The teenager is quick to promote the initiative.
"It was supposed to be for the elderly, but as we worked through the community we do it for everyone now.
"Anyone that requests that - we're more than happy to come out anytime. More than happy," Billy says.
Billy is also one of 60 nominations for a TCDC Youth Award. The 2015 Coromandel Peninsula Youth Awards celebrate the achievements of young people in the Coromandel Peninsula.
The Pride of New Zealand Awards are proudly brought to you by The New Zealand Herald, The Hits and TSB Bank.
Nominations for the 2015 awards have now closed.
To see more stories of our wonderful nominees click here.
For more information on the awards go to the official website.