Give some stream of consciousness and then the answer. A school shooting occurred at Marjory Stoneman Douglas High School in Parkland, Broward County, Florida, part of the Miami metropolitan area, on February 14, 2018. Seventeen people -- fourteen students and three staff members -- were fatally shot and seventeen others were wounded, making the shooting one of the deadliest school massacres. After being identified by witnesses and arrested by the Broward County Sheriff's Office shortly afterward, 19-year-old Nikolas Cruz confessed to being the perpetrator. He was charged with 17 counts of premeditated murder and 17 counts of attempted murder. Police and prosecutors have not yet offered a motive and are investigating "a pattern of disciplinary issues and unnerving behavior". The massacre surpassed the 1999 Columbine High School massacre as the deadliest high school shooting in American history.

Based on this passage, how old was the shooter in the florida massacre?
To answer this question, we should know that: After being identified by witnesses and arrested by the Broward County Sheriff's Office shortly afterward, 19-year-old Nikolas Cruz confessed to being the perpetrator.
Therefore, the answer is 19.