Two years ago, she was an 18-year-old YMCA summer counselor, working with children, preparing to enter University of Delaware. She was a budding artist with a devoted boyfriend in Brian Peterson, a telegenic high school athlete set to attend college just three hours away.
"Friends may come and go, but those who truly love you will never leave you," Grossberg wrote under her photo in the Ramapo High School yearbook.
Today, Grossberg marked her 20th birthday behind bars at the Delores J. Baylor Correctional Institution, sentenced Thursday to 2 1/2 years in jail for killing her newborn son, whose father threw his body into the trash.
"I'm extremely sorry for what happened to my baby. I blame nobody but myself," Ms. Grossberg said in the courtroom. "It's something I'll never be able to forget. That pain inside will be with me for the rest of my life."
With tears running down her cheeks, she told her parents she loved them as she was led away.
For his role in the baby's death, Peterson, 20, was sentenced to two years in prison _ a lesser punishment because he cooperated with prosecutors and tried to persuade Ms. Grossberg to seek medical help before she gave birth.
Peterson told Judge Henry duPont Ridgely: "Mistakes were made that cost my son's life and all I can say is I'm so sorry for what happened."
The judge read from letters Ms. Grossberg wrote to Peterson during her pregnancy, excerpts of which suggested the fetus was interfering with their sex life.
"Why won't it just go away?" she wrote. "I wish I could have my nice body back. ... All I want is for it to go away. I can't get caught."
The two former lovers from Wyckoff, N.J., wouldn't even look at each other across the courtroom Thursday, a stark contrast to early court hearings when they would hold hands and whisper to one another.
Police said Ms. Grossberg gave birth in a motel in Newark on Nov. 12, 1996, after keeping her pregnancy secret from her family and friends.
Peterson put the newborn in a garbage bag and threw it in a trash container behind the motel. An autopsy revealed the infant died of massive head trauma and was alive, not stillborn as both defendants believed.
Prosecutor Peter Letang said Peterson told them he heard the bag smack the trash bin, possibly accounting for the skull fractures listed as a cause of death. The baby also died of exposure and lack of oxygen.
Originally charged with first-degree murder and facing a possible death sentence, the two pleaded guilty to manslaughter this spring after their defense strategies _ and their relationship _ were hopelessly split.
Ms. Grossberg's lawyers initially said she didn't know why Peterson took her to the motel and believed the infant was stillborn. Any crime committed would be Peterson's fault, they said.
Peterson's legal team responded with a promise that he would testify against Ms. Grossberg, telling prosecutors she had ordered him to get rid of the baby.
Peterson also said he begged Grossberg to admit the secret pregnancy and seek prenatal care. His lawyers said he took her to an abortion clinic twice but she refused to go in.
In March, Peterson pleaded guilty to manslaughter and agreed to testify against his girlfriend. A month later, Ms. Grossberg pleaded guilty, too.
Robert Tanenbaum, Ms. Grossberg's attorney, appeared on CNN's "Larry King Live" late Thursday and accused Peterson of lying. Peterson had said his sweetheart had a seizure during the delivery and was not able to tell him anything, the lawyer said, but later told prosecutors Ms. Grossberg told him to get rid of the baby.
Peterson's attorney, Joseph Hurley, admitted during the program that Peterson changed his story, but insisted his client was now telling the truth.
Peterson and Grossberg could have gotten 10 years for manslaughter, though sentencing guidelines suggest exactly what Ms. Grossberg received.
If they receive credit in prison for good behavior and participate in education and work programs, Peterson could be out in fewer than 18 months and Ms. Grossberg could be released in fewer than 23.
Both will serve two years' probation and perform 300 hours of community service. Ms. Grossberg will counsel pregnant women to help them avoid the mistakes she made, her attorneys said.
Ms. Grossberg's attorney said she routinely visits the cemetery where the child is buried and weeps over the grave.
"I can tell you she lives in agony," Tanenbaum said. "Keep in mind, she was an 18-year-old and made a terrible mistake. And she's paying the price for the rest of her life."