They were hit by a pickup on Paseo Padre Parkway near Mowry Avenue in Fremont late Tuesday night.
"New Year's Day, you know, you get up and you think we're gonna start off a good new year and usually we get together right now, the family to cook and eat, well that's not happening," said the victim's aunt, Antoinette Rodriguez.
The news devastated the family of Ashley Capuchin. Most of her relatives found out Wednesday morning that the 19-year-old died on New Year's Eve.
Capuchin was hit by a pickup truck as she crossed Paseo Padre Parkway, carrying her baby in her arms. The 3-month-old child was also struck. He was rushed to Children's Hospital in Oakland in critical condition.
Capuchin's 17-year-old sister, Raina, who crossed the street with them, suffered non-life threatening injuries. It happened shortly before 10 p.m. Tuesday.
The two sisters and the baby were in a car that was stopped near the intersection of Paseo Padre and Mowry.
Lt. Fred Bobbitt explains what happened next.
"There was an argument that took place inside the vehicle they were traveling in," he said. "There were several parties inside that car. As a result, the two young ladies exited that car. We don't believe that they were arguing with each other."
The two sisters with the baby then walked onto Paseo Padre Parkway. They were hit by the oncoming truck in the middle of the street.
"She was excited to be a mom," Rodriguez said. "So many good things were coming her way. And so much change in her life for the good. And then this had to happen."
Wednesday nearly 100 people attended a vigil to pray for the mother and child.
"She just came to see us on Christmas Day to show us the baby. She was all happy, all lit up, just glowing. How pretty she looked man," said Charles Nunez, Capuchin's cousin.
"And from my understanding he got thrown 30 feet. So that's quite a ways for a little 3-month-old baby to get thrown," said Antoinette Rodriguez, Capuchin's aunt.
"I miss my granddaughter and I love her so much. She's in better hands right now. Just pray for my great grandson that he'll make it because he's in critical condition," said Gloria Rodriguez, Ashley's grandmother.
Police say the driver stopped and was cooperating with police. They say there is no evidence that he was under the influence of alcohol or drugs and will not be charged. Police say the victims were not in the crosswalk when the driver of the white truck struck them.
ABC7 News reporter Alan Wang contributed to this report.