Leah Washington, who turned 18 last month, was one of five people seriously injured in the Smiler crash at Alton Towers in June.
She had been at the theme park with her boyfriend Joe Pugh and was in the front of the carriage as it collided with another, leading to a rescue operation that would take four hours.
Miss Washington, from Barnsley in South Yorkshire, told the Mail on Sunday she begged the surgeon not to tell her she had lost a limb.
She told the paper: “It took me a long time to look at my injury. When I did, I burst into tears.”
She described seeing the other carriage in front and thinking the crash would be “like a bumper car ride”, but after the collision she saw that those around her were injured and realised the safety bar was digging into her left leg and saw flesh on the seat in front.
Looking to the future Miss Washington said she is apprehensive but is trying to get used to a different way of life.
She said she gets tired using crutches, but does not like being in a wheelchair as people often stare.
She said: “I’m nervous for the future. My life is on hold while my friends are moving forward, having their own cars and leaving home. I’ll have a different path and a different life.”
The teen said she does not feel anger towards the Staffordshire theme park, whose owner Merlin Entertainments has accepted responsibility for the crash, but added that she wants to know what went wrong so it does not happen again.
Vicky Balch, 20, from Leyland in Lancashire, also had to have her leg amputated after the crash.
Daniel Thorpe, a 27-year-old hotel assistant manager from Buxton in Derbyshire, Chandaben Chauhan, 49, of Wednesbury, West Midlands, and Mr Pugh also suffered injuries.