Min Kym got a cheap violin at six, passed her grade 4 music exam eight weeks later, and at seven became the youngest-ever student at the Purcell school. Twenty-five years later, the professional musician’s precious Stradivarius – worth £1.2m – was stolen as she ate a sandwich at Pret a Manger in London’s Euston station. After a huge criminal investigation, it was found three years later. Her memoir, Gone: A Girl, A Violin, A Life Unstrung is published this week.

Your child prodigy narrative is atypical. Your parents weren’t pushy: you played violin simply because you were sitting with your mum waiting for your sister to finish her piano lessons in a local music school, you were bored, and there was a space with the violin teacher at the same time. Does your career feel like blind luck?
It was all a set of peculiar coincidences. I mean, my mum found the music school in the Yellow Pages! They were winging it, really. But I found playing the violin really fun straight away – it wasn’t like work. My first teachers would tell me the stories about the pieces I was playing, so it was like getting lost in their worlds. Sometimes I’d make stories up – I’d mix up the story of Icarus with Wieniawski’s Légende and imagine the bird flying close to the sun as I was playing.

What is it like being a child prodigy – or, as you say in your book, one of the “cuckoos in the nest, oddities, freaks”?
You develop a dual personality. You’re a child absorbing everything in the world, but you’re also becoming an adult very fast, because the world you’re in is full of adults. You also think that’s normal, because you’ve never experienced any other kind of life. But I also went to my local state primary school when I was first playing, and there I did normal things, like talking about the TV shows I liked. Even when I got older, I never talked about my performing off stage. You’re you, but you’re not you.

In your adolescence, you suffered from anorexia. Was this exacerbated by your peculiar life?
I see it as a growing pain. Adolescence is a difficult stage for everybody. Your body’s changing so much, and when you’re playing in public, there’s this added sense of responsibility. Looking back, I was having to juggle so many different things, and it came out that way. But then I fell in love with someone, and I got through.

Your book also reveals your family’s extraordinary backstory in Korea. There’s the story of your uncle, then a 12-year-old boy, having to amputate your grandmother’s leg after their house was bombed during the Korean war, giving her a bottle of whisky to numb the pain, and following instructions from a book… how did those stories affect you growing up?
I’ve never not had my grandmother’s life in my head. She lost so much blood, and to survive that, to have to reconstruct her life while bringing up seven children… and she remained so positive after that. What an amazing example that set. The 1950s and the division of Korea is so recent, really, and it’s so easy to forget that.

As you grew up and had boyfriends, did you find your violin to be the third party in your relationship?
It’s very difficult for some people to accept. Playing music for a living isn’t work; it’s love, really. I say in the book that my schoolgirl crush was Beethoven’s 4th. Then there’s Bach. Music begins and ends with him. If I want a cleanse, I play Bach – he’s the ultimate detox! Then there’s your relationship with an instrument, which is even more intense.

What makes a violin like the Stradivarius you had worth so much money?
It’s a curious combination of elements. First, it’s an actual work of art, beautifully constructed – it could stand alone in a great museum, although for a player that would be a tragedy. Then there’s the relationship between a violinist and their violin, which has an incredible value, but that doesn’t have to be about money. I have a real old banger of a car, for example, but I love it and would never trade it.

Your Stradivarius was stolen after your boyfriend at the time convinced you not to have it under your chair, as you usually had it. Minutes later, two professional thieves already well known to police had taken it. How vividly can you recall that moment?
Time just stopped. When I’d found the Stradivarius, it was mine, like it had been waiting for me my whole life. When it had gone, I shut down. I genuinely had to go through the stages of grief to accept that it had happened.

Then when the violin was found, you couldn’t afford to get it back, because it had been vastly under-insured, and you’d already bought another instrument – and even selling that wouldn’t help get it back. How have you dealt with that emotionally?
Writing this book’s been part of that process. I felt I really needed to do it to clarify what actually happened during the theft, and to gain perspective. But the most surprising thing that happened by doing that is that I’ve discovered a voice that I didn’t even know I had. I found a new identity outside it.

Who are your heroes outside music?
Van Gogh. After the theft, I went to the National Gallery one day, stood in front of Long Grass With Butterflies, and just burst into uncontrollable tears. Imagine the other people seeing me – it’s so embarrassing! But to see this incredible painting he did, in the sanitorium, near the end of his life, with no perspective at all, but so vibrant and alive… it made me realise, come on, Min, you can do this, you can move on. After that, I started the book.

What is your violin now?
It’s an Amati. Amati was Stradivarius’s teacher, so it’s nice to still have that connection. It’s different – it’s not as powerful – it’s not the love of my life. But it has very beautiful qualities, and to find different corners and colours in its sound is a real privilege. Also it hadn’t been played for 100 years, so it was a great privilege to wake it up.

And what was the last piece you performed on it?
The Brahms Violin Concerto in D, a piece I always associate with my old instrument. It was the first time I’d played it since the theft in 2010. It finally felt the right time to face it again, to play it again. And I’m delighted, and relieved, that I really enjoyed it.

• Gone: A Girl, A Violin, A Life Unstrung by Min Kym is published by Penguin Random House (£14.99). To order a copy for £12.74 go to bookshop.theguardian.com or call 0330 333 6846. Free UK p&p over £10, online orders only. Phone orders min p&p of £1.99. Min Kym will be in conversation with Susan Cain on 6 April at St John’s Church, Hyde Park, London W2, 7-8.30pm, hosted by Waterstones