Christina-Taylor, 9, was the youngest victim of Saturday's shooting. She was born Sept. 11, 2001.
Christina-Taylor had just been elected as president of the student council at Mesa Verde Elementary School.
Roxanna Green, Christina-Taylor's mother, said her daughter had attended the event to learn "more about the political process."
Christina-Taylor is the granddaughter of former Phillies manager Dallas Green. Her father is John Green, a scout for the Los Angeles Dodgers.
Christina-Taylor was taken to Giffords' informal town hall meeting by a neighbor, said her mother.
The girl had recently received communion at St. Odilia Parish in Tucson, where she also sang in the choir. Christina-Taylor was the only girl on a boys little league baseball team.
"She was a beautiful girl inside and out," Green said. "She was wonderful and very intelligent."
The oldest victim in the tragedy, Phyllis Schneck, 79, was remembered by friends on Facebook.
"She was a member of our church and of our craft group," Julie Crane posted on her Facebook wall. "I will miss her great disposition, her laugh, and smile. She was always a helper, such a sweetheart. Our prayers go out to her children and grandchildren."
Crane attended Norminster Presbyterian Church with Schneck and was on the crafts committee with her, she told ABC News. Members of the church remembered her at services Sunday.
"There were a lot of tears today," Crane said. "We're going to miss Phyllis a great deal."
Schneck had received a robo-call from Giffords and went to the political gathering to see her speak, Crane said.
"She was very interested in what our government is doing," Crane said.
The grandmother was known for her ability to bake sweets such as almond cookies and brownies with mint chips in them. She also was a talented seamstress, sewing beautiful quilts, Crane said.
Schneck was a widow who spent part of the year in Tucson and her summers in her native New Jersey. She was a mother of three and a grandmother.
"She was very outgoing, She was always active in the community," Schneck's son, Ernest Schneck, told WABC. "She loved to cook. She loved to bake. ? She liked to make quilts and knit. She was a family person, she was very, very devoted to her family."
Also killed in the shooting was U.S. District Court Judge John Roll. Roll, 63, had served on the U.S. District Court for the District of Arizona since 1991.
"He was a good judge," said retired Chief Judge Thomas Zlaket, who sat on the bench with Roll. "But first and foremost he was a good human being."
Tucson Bishop Gerald F. Kicanas recalled that Roll often attended early morning mass before work.
"Judge Roll was a person of great faith and great integrity," Kicanas said in a statement. "He lived his faith as a servant of our nation for the cause of justice."
Roll leaves behind a wife, three sons and five grandchildren.
Gabriel Zimmerman, a staffer for Giffords, also died. Zimmerman, 30, was the director of community outreach for the congresswoman.
He had organized the "Congress on your Corner" event.
"I got a call from Gabe's fiancee, Kelly, saying some people have been shot," Zimmerman's father, Ross Zimmerman, said.
Gabriel Zimmerman had been looking at wedding chapels last week with his fiance, Kelly O'Brien.
Zimmerman, an avid runner, had been a social worker before joining Giffords' staff in 2006.
"He had a real knack for connecting with people," Zimmerman's father said.
ABC's Christiane Amanpour contributed to this report.