Hayley Okines is 12, but you couldn’t tell by looking at her.

Okines, of East Sussex, Britain has a rare disease called progeria, which causes her to age eight times faster than normal. Okines is 12, but she has the body of a 96-year-old, the Daily Mail reported.

One in eight million people suffer from this genetic disorder, and live an average of 13 years. Okines’ best friend, who also suffered from progeria, died in 2006.

Despite the arthritis, lack of appetite and the cocktail of pills that bedevil her morning and night, Okines has started attending secondary school.

“We were worried because of the sheer size of the school and of rough and tumble because Harley is quite fragile,” Kerry Okines, her mother, told the Daily Mail. “But she settled in quickly and has made a couple of new friends as well. She is particularly good at science and math.”

Okines has been open about her disease. In 2007, she was the subject of a British documentary series called “Extraordinary People.” At the time, she was preparing to participate in a clinical trial in America that tested the effectiveness of a drug, originally developed to treat cancer, on progeria.

She was one of the first progeria patients to try farnesyltransferase inhibitors (FTI), which a 2006 UCLA study found were effective in reversing the effects of progeria in mice. After two years of taking the FTI drug, she added another drug that is used to lower plasma cholesterol levels.

“We haven’t got official results back, but Hayley’s skin is a bit plumper. She has grown fine eyelashes and eye brows and has grown a bit as well,” Kerry said.

Okines will return to Boston this July for another check-up. But before that, she will be featured on “Extraordinary People” again Tuesday.

“She is a fighter and has achieved a great deal in a short time,” Kerry said.

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