Her Little Bundies range of characters are now on sale in one of Britain's top toy stores, Hamleys.
Newsround's Leigh Mytton caught up with Luisa to uncover the secret of her success.
When did you start designing the toys?
Three years ago, I got some modelling clay for my birthday. I started making models. My friends really liked them, so I carried on making them, and started selling them.
Luisa with two of her designs
Where did you get your ideas from?
I just made them up. I've always been really creative. I love drawing and writing stories. I thought about cuteness and what girls like. I get inspired by things and people.
When did you realise it could become a business?
My friends started saying 'can I have one of my dog?' and things like that. I had these order forms and they soon started piling up. I've personally made around 13,000 models. Two companies are now licensed to produce them, but they're still my designs.
Luisa with her little cousin who inspired her designs
Which is your fave Little Bundy?
Olivia. I designed it first then I thought it looked like my little cousin, who's two-and-a-half.
You're doing your GCSEs next year. How do you manage to keep up with your business? I fit it in around my school work and at weekends. It's just like doing any other hobby, like swimming.
What do you want to do as a career?
I want to be a product designer, doing toy design, gift design - that kind of thing.
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I road tested this year's new toys!
