A stunning woman in her early 20s models a gold bauble crystal bracelet, and another made of silver flowers. She appears every inch the chiconomic dresser, someone appropriating couture style at cost price. Her trendy exterior, however, belies the complexity of her life.

Jade Randeria, 20, is the founder and managing director of the online jewellery company Talullah Tu, based in Ilford, Essex. Last year her life was turned around when she was diagnosed with Asperger's syndrome, which can be a less obvious form of autism. Those who have Asperger's often display many of autism's classic symptoms: difficulty interacting, socialising, communicating, and often don't possess what is termed "social imagination", or figuring out what someone else is thinking (though they often have less difficulty speaking that those with other forms of autism). Many people with Asperger's lead normal lives, possibly with their diagnosis going unnoticed for many years.

Around 300,000 British adults are affected by some form of autism; a third of those people often cannot find jobs because of its associated difficulties. According to the National Autistic Society, only 23 per cent of the general public realise Asperger's is a form of autism. While Randeria could be said to suffer from a mild form of the condition, there is no doubt she has triumphed where others might not.

"When I was a teenager I felt like I didn't fit in," she explains. "I had a lot of friends but I never felt like I was on the same wavelength. As a young child I was told my behaviour was different – though I always knew that."

The fact that her condition was not detected when she visited a child psychologist during her early years at Beal High School in Ilford is quite common, says Tracey Sands, a spokesperson for the National Autistic Society. "We are increasingly hearing about being diagnosed later in life, even towards the age of 60," she says. "People who are slightly older are more likely to go out and seek diagnoses, after, say, seeing it on television. These days the system is much better at picking up people's cases."

For Randeria that came too late. "I found it hard to get on with people," she continues. "I always overanalysed everything to an extent that no one else did. When I was 15 or 16 I used to misbehave a lot. I just didn't want to be at school. That was despite me getting really good grades."

While Randeria was expected to achieve brilliant results for her GCSEs, she failed to achieve them because she stopped attending school. She did well enough to return for her A-levels, though, and then attended the University of East London in Stratford. But she still felt she lacked direction.

"I didn't know what I wanted to do, and that was always a big thing for me; I needed direction," she continues. "So my mum wanted me to go to university. She said it would be a waste if I didn't. But I was terrified. I ended up dropping out in the first week. I didn't like being around too many people. You have to have all these acquaintances; I would much rather be around familiar people."

The reasons for this are numerous; those suffering from Asperger's may have difficulty understanding hand gestures, facial expressions or tone of voice; they also might have problems with other social conventions which many of us take for granted – for example, knowing when to start or end a conversation and picking things to discuss with people.

That led to a quiet moment of desperation for Randeria: she knew she needed to find something to take her mind off things, and fast. "After university I got pretty depressed. It was made worse because my nan, who I was very close to, died. That had a big effect on me."

Last year she went back to a psychologist and after a few sessions she was diagnosed with Asperger's. "I then did an IQ test and discovered that my IQ was 164. I was deeply shocked, I had no idea," she continues. "After that I joined Mensa. Suddenly it all fell into place, I realised why I felt different to everyone else."

It is common for people with Asperger's to have average or above average IQs. After a bit of family research, she realised that her grandfather, someone the family had always described as "having a distinctive personality", had a photographic memory. "To be a female and be diagnosed with Asperger's is rare in itself," she adds. "But I think I must have inherited his IQ and personality; he was a very clever man."

Randeria then decided to channel her energies. Taking on her mother and grandmother's love for vintage jewellery, especially the vibrant, bold designs of the 1950s, she launched her website, which she designed herself; it has since won massive plaudits from the fashion press and sales are on the up.

"From a very young age I had a strong feeling that I didn't want to be ordinary," she concludes. "Throughout childhood I had always asked my mum, 'What am I good at?' And like most mums, she always replied, 'You are good at lot of things,' but I wasn't at all happy with that. I didn't just want to be good at something, I wanted to be outstanding, to really shine at something and be the best at whatever I did." It looks like Jade Randeria is on the way.