Her boyfriend's unmentionable flaw: his skin color.
"He could have beat me and been white, and they would have been OK with it," said Mitchell, who is white. "I was disowned by my family, because of my racial decisions."
At 17, she decided to break the silence, and she continued dating men of other races. She is now one-half of an interracial marriage. Her husband, Celvin, is black.
Some things have changed since the secrecy required in her adolescence, but other things have remained the same.
"I see the looks and the rolled eyes when they see my ring," said Mitchell, 29. "There are plenty of long-lasting relationships, though. Our situation is becoming more common."
The North Augusta couple represent a growing number of people who share their vows with someone of another race. Nationally, interracial marriages make up 8 percent of all couples, up from less than 2 percent in 2000, according to U.S. Census data. The Pew Research Center recently released data, based on the 2008 American Community Survey, that shows one in every seven new marriages in that year were between people of different racial backgrounds.
Asians were most likely to marry outside of their race, with 31 percent, followed by Hispanics with 26 percent, blacks with 16 percent and whites with 9 percent, according to the data. The South had the second-highest number of new interracial marriages in the nation, with 13 percent.
The multicultural pairings are becoming increasingly common, but the marriages have not yet been accepted as a norm, said Stephanie Coontz, the director of research for the Council on Contemporary Families, based in Chicago.
The unions were shunned by society and the legal system just 43 years ago. In 1967, a U.S. Supreme Court ruling struck down anti-miscegenation laws, which mainly existed in the South.
The court case, Loving vs. Virginia, came after the couple fighting the laws had been dragged from their beds by local law enforcement.
The groundbreaking case evoked change, but the Pew Center's finding shows black-white couplings are still the least likely, with only about one in nine of those marriages in 2008.
"Despite all the talks about a post-racial society, it doesn't exist yet," Coontz said. "We've seen an increase with the younger generation, and I think the increasing age of marriage has made the difference. They're out on their own, so they have the freedom to be with whom they want."
When the Mitchells arrive at Tabernacle Baptist Church, they both stand out. He's 6-foot-5; she's one of a handful of white members at the historical church.
The two met at Tabernacle seven years ago and had an instant connection, said Celvin Mitchell, 29. Growing up in a military family, he made friends with people from different backgrounds, he said.
"Ignorance was not tolerated," he said. "I wasn't looking for a particular race when I met her. I just believe love is color-blind."
Carrie Mitchell said marrying her husband in May 2009 confirmed her belief that her family's viewpoint was wrong. Though her family still disagrees, her mother now supports her interracial marriage.
Celvin Mitchell said he ignores some of the side glances when he, his wife and two children enter a restaurant. He contends that most people have come to accept it.
"It's really the people in the older generations that are stuck in their ways," he said. "There's a mentality and fear about co-mingling, but I think people my age are more accepting."
Tara Hampton said her mother still laughs when they speak of her husband, Aaron.
"She jokes about her white son-in-law," said Hampton, who is black. "I would say she was from the old South, but she doesn't have an issue with it."
Aaron Hampton, 23, said he finds humor in people's fascination with their union.
The Hephzibah couple began dating in 2007 and married in December. Both agree it still feels like the first date.
"We just make each other laugh. He's always so affectionate," Tara Hampton said. "If you find someone who makes you happy, you have to hold on to that."
She said she has had friends say they accept her marriage but that they would never date or marry outside of their race. The hesitation from her friends and others stems from their families' views.
"It's heart-wrenching that people feel that way," she said. "For me, I cannot base my marriage on what my mother or anyone thinks. When it's all said and done, it'll be me and him. I have to be happy with that."
By the time the couple have a child, Aaron Hampton said he hopes the lingering stigma will have dispelled.
"I didn't set out to marry a black woman, but it turned out that way," he said. "I hope people start to see it that way. I'm overlooking the disrespect, because my focus is on her."