The girl and several friends had been on the roof of the building, located at 110 L St., jumping between sections when the girl fell though the skylight at about 6 p.m., Orman said.
She plummeted about 20 feet to the floor below, narrowly missing a pile of debris.
"She was lucky," Orman said.
He said she didn't appear to have suffered any serious injuries or broken bones, but might have gotten a concussion.
Her friends called for help and the girl was transported to John Muir Medical Center in Walnut Creek for treatment.
The other teens were cited for trespassing, Orman said.
He said there was no indication that the teens had been drinking or doing drugs.