Hillsborough Circuit Judge Christopher Nash heard hours of testimony on Thursday before announcing his decision to send Cameron Herrin to prison.
“It’s impossible to have greater harm than occurred in this case,” the judge said.
Herrin's family members began to weep as sheriff's deputies placed him in handcuffs after the hearing, the Tampa Bay Times reported.
“I feel responsible for this accident,” Herrin's mother, Cheryl Herrin, told the judge on Thursday. “If I could, I would step in front of Cameron, and I would accept the punishment you might render.”
Herrin hit Jessica Reisinger-Raubenolt and her 1-year-old daughter Lillia with the Mustang he'd received for his high school graduation two days earlier. They were visiting Tampa from Jeromesville, Ohio.
He was heading to a gym on the morning of May 23, 2018. Witnesses later told investigators that Herrin and his friend John Barrineau, who was driving a Nissan, appeared to be racing on Tampa's Bayshore Boulevard. Police said Reisinger-Raubenolt, 24, was pushing her daughter in a stroller when Herrin's car hit them.
Barrineau also pleaded guilty and is serving a six-year prison sentence, WFTS reported.
Prosecutors presented evidence that the Mustang topped 100 mph (160 kph) moments before the crash, rapidly decelerating to 30 and 40 mph (48 and 64 kph) at the time of impact.
David Raubenolt spoke for nearly an hour, telling the court that his wife loved children and was a parent who passed out notes to airplane passengers, apologizing if their child started to cry. He said he sweats when he enters his daughter's room, where her crib remains untouched.
“It is critical for you to understand that you’ve created everlasting pain and depths of sorrow,” he said.
This story has been edited to correct the spelling of the victim's name: Reisinger-Raubenolt.