A 16-year-old Philadelphia girl sentenced to 2½ years in prison for pummeling a Temple University student with a brick will soon be the youngest female in the state's adult correctional system, officials said Thursday.

Common Pleas Court Judge Michael Erdos issued the sentence Wednesday, saying he was trying to strike a balance between Zaria Estes' age and the seriousness of her attack on Abbey Luffey, who sustained a fractured jaw and palate, and broken teeth.

In March, Luffey had been walking with her boyfriend at 17th and Norris Streets when Estes attacked her without provocation. Two other girls joined Estes in attacking Luffey, but used only their fists. They are being tried as juveniles.

Department of Corrections spokeswoman Susan Bensinger on Thursday said Estes, who remains in custody in Philadelphia, will be sent to a special housing unit at SCI Muncy in Lycoming County.

The unit has six other women under 21, including a convicted murderer and a robber, Bensinger said. Under federal law, state inmates under 21 must be isolated from adult prisoners.

Bensinger said female prisoners as young as Estes are rare. She said that since the 1970s, the state prison system has had only three female inmates younger than Estes. She said the state has developed the appropriate programs for the young women.

Lauren Fine and Joanna Visser Adjoian of the Philadelphia-based Youth Sentencing and Reentry Project, however, said that despite the Department of Corrections' assurance that programs were available for the young offenders, they believed Estes was unlikely to get the help she needs in an adult prison.

Estes' lawyer, William Davis, has asked Erdos to postpone sending his client to state prison until an appeal can be filed on the judge's initial decision to try her as an adult.