Tavares Spencer, 16, was tried as an adult on charges that included attempted first-degree felony murder, attempted second-degree murder and robbery; he was found guilty on October 30.
Tampa police said Spencer met up with Terrience McDonald in April and that he believed she was biologically female.
Police said Spencer was so irate when he learned McDonald was biologically male that he lured McDonald into a vacant house and shot her.
Soon after the April 9 shooting, Spencer bragged in text messages about the incident, using graphic and derogatory language to describe McDonald.
Sgt. Michael Stout of the Tampa police said at the time of the arrest that detectives were taken by Spencer’s lack of remorse in the incident.
“My grandson has a very good heart. He’s funny. He’s kindhearted,” Keaton said.
But the judge ruled that Spencer had demonstrated a progressive pattern of criminal behavior before handing down the 25 year sentence.