Taquesta Graham was extradited from Texas to California last week.
She had been scheduled to be arraigned Wednesday, but the proceeding was continued to April 16. She is being held on $2 million bail.
Other family members are holding a funeral service for Trinity next week and are welcoming the public to attend.
The service will be held Monday, March 25 at 12:30 p.m. at St. John Vianney Church, 1345 Turnbull Canyon Road, Hacienda Heights.
"I'm grateful that God let me borrow this angel for 9 years," said Tony Jones, Trinity's father.
Graham and her boyfriend Emiel Hunt are accused of killing the young girl on or about March 1. Trinity's body was discovered along an equestrian trail near Colima Road and Hacienda Boulevard on March 5.
MORE: Hacienda Heights girl killed: Makeshift memorial growing on trail where body found
Hunt was charged earlier this month with one count of murder in the same case.
Graham faces a maximum sentence of 26 years to life in state prison if convicted as charged, prosecutors said. Hunt faces up to 55 years to life in prison.
Trinity's family members came to the Pomona courtroom and said it was difficult to see Graham there.
Trinity's maternal grandmother often watched Trinity as she was growing up and was crushed by her death, family members said.
Debora Kent, who is Graham's aunt, said Trinity's grandmother "mostly raised Trinity. She always had Trinity. It's just like her losing her baby."
Anyone with information about the child's death is asked to call the sheriff's Homicide Bureau at (323) 890-5500. Tips may be submitted anonymously by calling Crime Stoppers at 800-222-TIPS (8477).