It was supposed to be a week of joyous milestones for Shelly Mulkey.

Mulkey, 19, was getting ready to celebrate the first Christmas with her 7-month-old son Ryan, The Advocate reported. She learned last weekend that she was pregnant with a second child, and Ryan McCollum — father of the two babies and her longtime boyfriend — had just proposed to her.

But, hours after Mulkey said yes, the three were leaving a party on Christmas Eve near Tickfaw, Louisiana, when a suspected drunk driver plowed into the back of their car, according to KATC.

The crash was so strong that, police said, it caused Mulkey’s 2005 Dodge Stratus and the vehicle of the speeding driver to burst into flames.

Witnesses of the fiery crash removed McCollum and Mulkey from their flaming car, but their baby was inside the burning vehicle until firefighters extinguished the flames, KATC reported.

Witnesses gave Mulkey CPR, but it was too late — she and her 7-month-old Ryan died at the scene, according to WAFB.

Just hours after proposing to his four-year girlfriend, Ryan McCollum is trying to make sense of losing his soon-to-be wife and his son, who he described as “the best baby you ever seen in the world.”

“She was an awesome mama and an awesome friend,” he told The Advocate. “I just want to hold them both in my arms again so bad.”

Police identified the woman who crashed into Mulkey’s car as 36-year-old Jillian Pamela Ramsay, who is believed to have been drunk, WGNO reported. She was driving away from another car she had just crashed into before slamming into Mulkey’s, police said.

Ramsay had only minor injuries and could exit her car, WGNO reported.

Ramsay was arrested after leaving the hospital and police charged her with Vehicular Homicide, Hit-and-Run, and Careless Operation, WAFB reported.

“That’s three lives she took from me,” McCollum told The Advocate. “That woman is going to have to live with that the rest of her life.”