But that real world disrupted her life on Aug. 29, 2005.
McCoy had been a teacher for 12 years at Robert Russell Moton Elementary in New Orleans' Lower Ninth Ward, the neighborhood in which she grew up.
She lived in Harvey, La., on the west bank of the Mississippi River, with her husband, Jason McCoy, and their nearly 2-year-old daughter, also named Letrece.
"I told my co-workers that Friday before Katrina hit, 'I'll see you Monday,' " she said. "We knew the hurricane was coming, but we all figured we'd be out one day, at most till Wednesday. Some of those people, I've never seen since."
The floodwaters destroyed Moton, which was one of the newest schools in New Orleans. High water reached the entrance of McCoy's apartment complex, but did not get in, though her home sustained wind damage.
As soon as they could, the McCoys packed their belongings and traveled in a caravan of vehicles with Jason McCoy's father, Darryl Glenn McCoy, and other members of their church, Trumpet in Zion Fellowship, to Augusta, where other church members helped them resettle.
It wasn't long before Letrece McCoy landed a job at Windsor Spring, teaching second grade. After teaching without much fanfare in New Orleans, McCoy was quickly noticed by Windsor Spring's leadership.
She became part of the school's instructional leadership team. She was named Windsor Spring's 2009 Teacher of the Year. She helped the school implement a Web-based program that monitors pupils' math progress. She received two Universal Silver Teaching Awards from Voyager Universal Learning System for her work with that math curriculum.
What sets her apart, her students and peers say, is her effort to make her pupils understand the math concepts she teaches by applying them to real-life situations.
"You have to know math to pay bills," said 10-year-old Taylor Charles, who has known McCoy since he was in second grade.
"She's devoted to her children, but she wants them to be responsible for themselves," said Sharon Wells, instructional coach at Windsor Spring. "She wants them to know real-life situations."
McCoy, 39, said she relied heavily on her faith to make it through the frightening times in New Orleans. She still wonders what happened to some of the friends and colleagues she has not seen or heard from since Katrina. The building of the church she was part of was destroyed, but that ministry has since relocated to Gulfport, Miss., and she is the youth choir director and singer on the praise team at Augusta's Trumpet in Zion Fellowship. Her husband is a traveling musician with the church.
They have had two children since moving here: April Marie McCoy, 2, and Jason McCoy Jr., who was born just seven weeks ago, on July 25. Young Letrece will be 7 in November.
McCoy says she feels comfortable in Augusta and has no plans to move back to New Orleans, though she does acknowledge missing the food there.
"They call New Orleans the city that never sleeps," she said. "After we moved here, my husband and I would say it's too bad we can't go out and get a po' boy. There were restaurants open at 2 or 3 in the morning where you could get something to eat. Here, everything shuts down at a certain time."
But her life is here now. Her areas of focus are God, her family and her students at Windsor Spring.
"I love being part of the fifth-grade team," McCoy said. "We work together as a family unit. We shut the building down sometimes (from working late on lessons). Our children are able to be tutored from us at a time way past school hours if they need it.
"We try to be very supportive of them."