The eighteen-year-old lost his lower legs and spent nearly a month in hospital after the accident.
It happened during a race at Donington Park, days before his birthday.
When he was recovering from his accident, Billy said he really wanted to race again, despite his injuries,
Now the Formula 4 racer is back behind the wheel - trying out a car specially designed to make it easy for him to drive.
The controls for the Fun Cup endurance racer are attached to the steering wheel instead of being the floor of the car, where they'd normally be.
The new racing car came from a group called Team BRIT. They help disabled people and people with injuries that would making driving difficult, to compete in motorsport.
It's designed to look like a Volkswagen Beetle, and Billy's been giving it a test drive at Brands Hatch in Kent.
Billy says it's been really good just to get back behind the wheel, but he still wants to perfect his technique and get used to driving the new car.
While Billy still has some training and therapy to get through, he says that's all going well, and he's hoping to get back out on the track properly soon.
He says his ambition is now to compete in the Le Mans 24 Hours, along with Frenchman Frederic Sausset, who lost both his arms and legs through an illness.
The teenager also wants to thank his fans, saying he's been overwhelmed by the help they've given him.
He says: "People keep saying I'm the inspiration but I think all these people coming together to support someone who has gone through an accident like this, they're the true inspiration."

Martin Shkreli's drug company Turing Pharmaceuticals bought the rights to 62-year old drug Daraprim and increased the price per pill from $13.50 to $750.
Turing said it will cut the price by 50% for hospitals and offer financial assistance to individuals.
However, the company will keep its list price at the new higher level.
In September Turing promised to reduce the price.
The pill costs around $1 for patients in Europe.
In statement Turing's chief commercial officer Nancy Retzlaff defended the company's move. She said that reducing the listing price would not have translated into saving for patients.
"Drug pricing is one of the most complex parts of the healthcare industry. A drug's list price is not the primary factor in determining patient affordability and access," Ms Retzlaff said.
Doctors though worry keeping the price so high will make it impossible for hospitals to stock the drug for the few patients who need it.
"The decision not to lower the price leaves patients in the same boat," said Dr Joel Gallant, medical director of special service at Southwest Care centre.
Though Turing is offering payment assistance for some patients, Dr Gallant said this could still leave patients waiting for treatment.
"Patients start the drug in the hospital, but then they need to be discharged with the drug. While they wait for patient assistance to be approved they could be re-hospitalised," said Dr Gallant.
The original increase sparked outrage on social media and among politicians.
Democratic presidential candidate Hillary Clinton called the increase "price gouging".
Turing's chief executive Martin Shkreli- who had been labelled the most hated man in America-fought back saying politicians did not understand Pharmaceutical pricing.
He later backed down and promised to lower the price of the drug, though never said by how much.
Mr Shkreli told ABC news in September, "'We've agreed to lower the price of Daraprim to a point that is more affordable and is able to allow the company to make a profit, but a very small profit."

Officers were called at about 02:30 BST following reports that a man in his 30s had been attacked in Greenbrow Road, Wythenshawe.
He was taken to hospital but he died from his injuries.
Supt Steve Howard, from Greater Manchester Police, said: "We are working hard to piece together what happened to the man."
Teenage racing driver Billy Monger has returned to the racing track, almost three months after he was badly hurt in a crash.
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