Antoinette Baker, 30, was stabbed to death early Sunday morning with a beer bottle outside Hartigan's Irish Pub.
Police said Baker and several others were fighting in the bar, and the fight spilled out into the alley when the bar management kicked them out.
Police charged Katie Nicole Robinson, a former Charlotte Mecklenburg Schools bus driver, with murder.
More than 100 people turned out for Friday's vigil, including Baker's mother and six children.
J.J. Baker, 11, bravely took the microphone and talked about how he wants to live his life now that his mother is gone.
"I have to be strong for my grandma and my brothers and sisters and my family. So I have to look out for them and for everybody else. And I have to make sure that this doesn't happen to them either," he said.
In her last Facebook message, Antoinette Baker on Saturday said she was grateful for J.J., and proud that she was celebrating his birthday.
Just hours later, family members were posting on Facebook their condolences and grief.
"I need to do what she wanted me to do, which is take care of my brothers and sisters and do something with my life," J.J. Baker said.
Close family friend Lashanda McKinney took the microphone after J.J.'s speech.
"I know that he wants better for y'all. She's watching over y'all, and I'm praying to God that one day He gives you all understanding," McKinney said.
Baker had six children. J.J. is the oldest at 11 years old; the youngest is just 2.
Her funeral is scheduled for Saturday.
Robinson is being held without bond on murder charges.