Her previous employment had been bagging groceries for tips in a Pathmark, wearing the uniform of the Catholic middle school she attended in the Bronx. That summer, in 2001, she was outfitted by a 21-year-old man who paid her less than she had made at the supermarket and brought her to Hunts Point.
"He gave me the little shorts to wear, and the little tank top thing to wear," said Ms. Johnson, now 22, who asked to be identified pseudonymously. "He told me: 'Just stand right there. When the car pulls up, just tell them, "You want to have a good time?" You tell them the price, then you go and do whatever.' "
For the next eight years, she was sold by men to men. She went through spells when her young body was bringing in $1,600 to $2,500 a night. All of it went to the pimps, she said. They gave her stiletto-heeled shoes, and Ecstasy, and two babies, and beatings with a stick for looking at other pimps.
On Wednesday, she will be part of a small, vital revolution in New York State. Her lawyers from the Legal Aid Society and prosecutors from the district attorney's office in the Bronx will jointly ask a judge to overturn her convictions on prostitution charges before she had reached the age of consent. A law that took effect in August 2010 recognizes that children and minors who perform sex for money are not criminals but victims, and says that they should not bear the residual burden of convictions.
If her request is successful, as is likely, Ms. Johnson will become the third woman in the state to have used the new statute to erase prostitution convictions, and the first United States citizen to do so, said Kate Mogulescu, a Legal Aid lawyer who is representing her.
How many girls are involved in similar situations? In 2007, the state commissioned a survey of every social services agency that had contact with minors in trouble.
In New York City, the study found 399 children who were first "commercially sexually exploited" at age 12 or 13, and 922 at 14 or 15. The state and city have made reforms to move young people like them out of the criminal justice system and to help them with social services.
"The majority of the girls out there had started when they were young," Ms. Johnson said. "They find a little bit of happiness in the game."
That means there are vast numbers of women who were arrested as minors on prostitution charges.
"This is a landmark moment," said Steve Banks, the attorney in chief at Legal Aid. "There are thousands of women who will benefit over time. It removes a blot on their lives."
Ms. Johnson lives in Georgia and works in a Waffle House, supporting her daughter, who is not yet 3. (An older son lives with Ms. Johnson's mother in the Bronx.) She hopes to get a second job, Ms. Johnson said, but the first question on a supermarket application was, "Have you ever been convicted?"
The court hearing on Wednesday will address three convictions for prostitution in 2006, when she was 17. Her pimp, who is under investigation and whom she did not want to identify, had given her false identification that showed she was over 18.
She grew up in the Bronx, the eldest of three daughters born to a hard-working single mother who ran her household with rules and attention that you might expect would keep a child from going astray.
As she tells her story now, a decade later, of the headstrong, damaged, bright, pretty girl that she was, it is hard to grasp all the forces that brought her to a life on the streets. In 2001, a few months before she first left home, her father, who did not live with the family but with whom she was close, was murdered in New Jersey. She cherished the attention of the older boys and men.
It came to an end in 2008, she said, when she learned that she was pregnant and was expecting a girl.
"There was just no way she could be around that," Ms. Johnson said. "Not having it."