"But then I woke up in the morning and went 'okay, there's got to be another way'."
She looked on TradeMe for second-hand cameras and found a suitable one, but it was still too expensive. So Rose contacted the seller, professional photographer Chris Parker, and told him she was 12 and wanted to get into photography.
"He said that he got into photography when he was 8 and he really loved the fact that I was trying to get into photography when I was really young, and so he gave me an even better deal and I got it for $550," she says.
Since then, Rose has barely stopped snapping, shooting portraits and product shots for local businesses, as well as the stills for locally-made film The Z Nail Gang.
"Originally when I started getting into photography, I wanted to be a director of photography on films, so it was really awesome being on set with them."
At this point you're probably wondering how school fits in with all this. Her mother Su-Ann says home-school is the answer.
"You'd be amazed how much of the curriculum is covered in running your own business," she says.
Rose handles all correspondence, website design and maintenance, her social media profiles, marketing and accounts.
She buys all her own gear and isn't shy to ask others in the industry for advice, often questioning them about the technical aspects of the gig.
"Rose is a big talker. She's not afraid of chatting to anybody," Su-Ann says.
That talent for talking comes in handy behind the camera too.
"I always find it's very important, while you're taking someone's photo, to talk to them," Rose says.
"A lot of people always say to me, 'Oh, I'm not very photogenic'. I always say 'everybody's photogenic', you've just got to find what makes them comfortable."
Rose is now venturing into videography and relishes the challenge.
"There are some things that I find hard about it. But I know that if I keep going on video, it'll be perfect like photography is."
Long-term, she says whatever she does, she'll definitely be behind a camera.
- To find out more, contact Rose at rosemcmahon.com or check out Little Miss Rose on Facebook.