I don't have many memories of being four, but I do recall my surprise at starting school and finding that my older classmates weren't all fluent readers like me. I think it came as a surprise to my parents, too - since I was their first child, they'd assumed there was nothing unusual in the speed at which I'd learned to read aloud.

Mum and Dad never "pushed" me. They enjoyed my inquisitive nature and answered questions, but I wasn't forced to recite my times tables every morning or switch off the television. I simply enjoyed learning, and when no one else was teaching me, I'd teach myself.

I was a natural mathematician, and later became a gifted oboe player and pianist, too. At 10, I was encouraged to audition for a place at Chetham's School of Music in Manchester. A friend I considered a better musician failed to win a place, so I was surprised and delighted when I got in. I now realise the examiners were judging potential rather than ability, and in those days potential wasn't something I lacked.

During my first year, I was a subject of an educational psychologist doing a study of gifted children. She measured my IQ and found it to be 169 - I've since been told that made me literally one in a million.

Perhaps Chetham's gave me unrealistic expectations. When I finished my maths O-level early, I asked if I could learn astronomy to fill the time. As with everything else, I took the exam and got an A. I thought things would always be that easy. At 17, I'd given my future little thought. My childhood dream of becoming a librarian on a spaceship remained the closest thing I had to a career plan. Cocooned in academia, it didn't seem to matter. When I left Chetham's with six A-levels, all A grade, even the press took notice.

My decision to pursue maths and astronomy at degree level led to headlines about me "reaching for the stars". I arrived at university with every expectation of proving them right. In fact, I was about to come crashing back to earth. My peers, who had learned to work hard for their A-levels, thought nothing of putting in extra hours at home, but I hadn't developed the self-discipline. Everything had come easily to me at school. I'd dash off homework on the bus and my grades never suffered. Now, for the first time, I found something I couldn't do. My whole sense of self was shaken.

I felt genuine shock. Bewildered, I did everything I could to avoid work. Living away from home for the first time, in London, distractions weren't hard to find, but every evening I came home to coursework that hadn't been done, and every day I found new excuses to avoid lectures and tutorials I couldn't face.

Inevitably, my grades suffered. I received warnings and ignored them. I'd never had to ask for help before, and didn't know how to. Having always taken my abilities for granted, it was hard for me to accept they had a limit. I flunked my second year exams. The sensible response would have been to immerse myself in study. Instead, I spent my third year producing a musical. Inevitably, I failed my finals, too, eventually scraping a third on retakes.

My parents were devastated. I felt terrible guilt, and dwelt on how old schoolfriends would react. Everyone I knew had expected great things of me, and I'd let them all down.

Still, I'm not sure what people expected of me. Rocket scientist or concert pianist? Which star was I meant to be reaching for? The great achievement remained undefined. Having a burden of expectation young makes disappointment almost inevitable. In fact, I went into teaching, which I did happily for 20 years.

The most common interpretation of success seems to involve a long career, good pay, a big family. I've hit my 40s, single, without achieving those things. Someone who is motivated and driven - irrespective of their IQ - will probably find it easier to reach those goals than a "brilliant" individual who lacks direction. On those terms, many people would consider me a failure, but I'm not ready to accept that. I've been thinking about where my real skills lie. Two years ago, I gave up teaching to concentrate on musical arrangement.

It's been a hard slog, but I'm starting to get commissions. I've had some positive responses, and it feels good to receive praise again. At last, I've worked out what I really want to do - and this time I'm willing to work for it.