BRUNSWICK, Ga. -

De'Marquise Elkins, convicted of fatally shooting a baby in the face while trying to rob the child's mother, was sentenced Thursday to life in prison without parole.

A jury convicted the 18-year-old of murder last month in the slaying of 13-month-old Antonio Santiago.

The boy was in his stroller and out for a walk with his mother in coastal Brunswick when he was shot between the eyes.

Elkins' sentence included another 105 years for the convictions on the lesser charges.

Sherry West, the toddler's mother, gave a victim impact statement, reading a poem she wrote and asking the judge to hand down the maximum sentence.

"The love of my life was taken away. All that's near is fear," said West. "His innocent blood spilled in mud, and a scar on my knee to constantly remind me."

In court, there was very little reaction when the judge made the decision.

"The court hereby sentences you to life in prison without parole," said Judge Stephen Kelley.

Elkins' attorney, Kevin Gough, said he was disappointed in the sentence, calling life without parole for a minor unconstitutional. Elkins was 17 at the time of the killing.

"Life without parole for a juvenile, with all due respect to the court, our position remains that is cruel and unusual punishment," said Kevin Gough.

Gough said the defense would appeal.

The toddler's father, Louis Santiago, is currently in jail accused of stalking West in an unrelated matter, but was allowed to be in court Thursday.

The Elkins family was also in court Thursday. They spoke to Channel 4 after the sentencing.

"I was like, 'Wow, he can never see daylight. His life is going to end.' I was crying because we were like really close to each other," said Elkins' sister, Alexis Williams.

"I want Marquise to keep his head up and read the 23rd Psalm every morning and every night, and just be strong," said Elkins' aunt, Hazel Etheridge.

Elkins' mother, Karimah Elkins, was convicted of tampering with evidence for disposing of the gun, but acquitted of lying to police.

Fifteen-year-old Dominique Lang, who is charged as an accomplice in the boy's death, is awaiting trial.

While Elkins' trial took place in Cobb County due to pretrial publicity in the Brunswick area, Thursday afternoon's sentencing took place at the Glynn County Courthouse. Under Georgia law, Elkins had to be sentenced to life in prison with or without the possibility of parole.