Tucson, Arizona (CNN) -- Nine-year-old Christina Green was ambitious, and she liked to be in charge.
She was the only girl on her Little League baseball team in Tucson, Arizona -- and she told others she wanted to be the first woman to play in the major leagues. Most believed she could do it, someday.
But her life was cut short by a gunman's bullet Saturday as she attended a congresswoman's meet-and-greet in a supermarket parking lot.
Christina's family, friends, classmates, and hundreds of mourners filled St. Elizabeth Ann Seton Catholic Church in Tucson for a funeral service Thursday afternoon, all of them passing under a giant American flag that was recovered in the aftermath of the terror attacks in New York on September 11, 2001 -- the day Christina was born.
Dozens of mourners paid their respects by standing outside the church, which was was filled to capacity.
Representatives from professional baseball also were in attendance. Green was the daughter of a Major League Baseball scout and the granddaughter of former baseball manager Dallas Green.
The girl's father, John Green, was the only speaker. Before the tearful crowd, he spoke directly to his departed daughter: "Christina-Taylor Green," he began, "I can't tell you how much we all miss you."
"I think you have affected the whole country," he said.
Christina was "a little girl with the wisdom of a wise woman," Bishop Gerald Kicanas said. "She has found her dwelling place in God's mansion. She went home."
"She wanted to make a difference with her life, to make her mark," he said of Christina. "She has done so in such a powerful way that even she could not have imagined."
Pink and white flowers, along with pink bows, adorned the church. The University of Arizona choir sang "Ave Maria." Family friend Katy Martin sang Billy Joel's "Lullaby." "Goodnight, my Angel, time to close your eyes," the song began.
The young girl had recently been elected to the student council at Mesa Verde Elementary School, and a neighbor -- impressed with Christina's civic interest -- took her to the event to meet Rep. Gabrielle Giffords.
"Imagine: here was a young girl who was just becoming aware of our democracy; just beginning to understand the obligations of citizenship; just starting to glimpse the fact that someday she, too, might play a part in shaping her nation's future," President Barack Obama said at a memorial service Wednesday night for those killed and wounded in the shooting.
"She had been elected to her student council; she saw public service as something exciting, something hopeful," the president said. "She was off to meet her congresswoman, someone she was sure was good and important and might be a role model."
Giffords, along with 12 others, was wounded when the gunman opened fire. Six people -- including Christina -- were killed.
Police say suspect Jared Loughner, 22, had complained for years about Giffords, after apparently getting a response he didn't like after asking her a question at a 2007 event.
The shooting set off a political firestorm across the country, with pundits charging that extreme partisan politics somehow played a role in the mass killing.
The president noted that Christina was just beginning to discover the political system -- something that she saw "through the eyes of a child, undimmed by the cynicism or vitriol that we adults all too often just take for granted.
"I want us to live up to her expectations. I want our democracy to be as good as Christina imagined it. I want America to be as good as she imagined it," Obama said. "All of us -- we should do everything we can do to make sure this country lives up to our children's expectations."
Christina's parents say they're just trying to get through it.
"It's minute-by-minute, day-by-day. We're just taking it slow. We're hanging in there, we're trying to be strong. We have to be strong. Our country's being strong, our community is being strong for us, so we will, you know, get through this with our faith and our friends and our family," mother Roxanna Green told CNN's Anderson Cooper Wednesday night, before the public memorial service.
Most of the mourners arriving for Christina's funeral service Thursday paused to look up at the huge flag that rippled between the extended ladders of two fire trucks outside the church. The banner, which has been patched with flags recovered from other disasters, was sent by the New York Says Thank You Foundation.
The gesture is precious to the Green family.
"We both let out a gasp of emotion, because, you know, that meant a lot to us," Christina's father told CNN. "And for them to extend that courtesy to our daughter ... again, it's just another one of those things that will help for us. We feel like the country won't forget her."
Christina was to be buried in a custom-made red oak casket donated by a group of Trappist monks in Iowa.
The lid of the casket was inscribed with her name, date of birth and death, and a cross. The family also will receive five small keepsake crosses hewn from the same wood as the casket, according to Sam Mulgrew, the general manager of Trappist Caskets.
Before the casket was sent from the monastery to Arizona, the Roman Catholic monks gave it a special blessing inside their chapel on Tuesday.
Obama met with the Greens before the public service Wednesday night.
"He expressed that there are no words, and to stay strong and believe in our country. And we've -- one thing we promised him is we would do that," John Green said, adding that Michelle Obama extended an invitation to visit the Obamas in Washington.
"We would be proud to be a part of that," he said. "I know Christina, you know ... that's something she would have loved to do."
The president also remarked on Christina's unique appreciation for life.
"She'd remind her mother, 'We are so blessed. We have the best life,'" Obama told the audience at the University of Arizona Wednesday evening. "And she'd pay those blessings back by participating in a charity that helped children who were less fortunate."
Her family has set up the Christina Taylor Green Memorial Fund, to help children in her hometown of Tucson. The act seems to fulfill one of the child-like wishes that accompanied a photograph of Christina in a book published in 2002 called "Faces of Hope: Babies Born on 9/11."
"I hope you help those in need," the message read.