Family members identified the girl as Giselle Mendoza, a sophomore at Palmdale High School.
Investigators said the driver, 20-year-old Roberto Rodriguez, lost control when he turned the corner on the 1000 block of Avenue R around 3:50 a.m.
Good Samaritans rushed to see who was injured, and they then kept Rodriguez detained in the SUV until authorities arrived.
Responding officers found the SUV embedded in the building. Mendoza was killed on impact.
"She meant everything, she was my little sister," said Yadira Mendoza. "What else can I say? We're just hurt. I can't believe this happened."
Devastated family members said Mendoza was always happy, and always had a smile for everyone she saw.
According to witnesses, Rodriguez lives right across the street from where the collision occurred.
Rodriguez was transported to a local hospital and treated for minor injuries. He was booked for vehicular manslaughter. Rodriguez has been released on $100,000 bail. He is due in court on Tuesday.