Atlanta (CNN) -- By the time Leikia Reynolds was 12 years old, her life was heading down the wrong path. Her grandparents took her in when she was 11 months old. She didn't know her mother, and her father was serving a 16-year prison sentence.
Her grandmother, Dorothy Reynolds, saw the warning signs.
"She was getting into fights. She saw other kids with parents, and she felt left out. She called me 'Mama' and my husband 'Daddy,' " she recalls. "She didn't feel good about herself. She was failing in math ... she didn't have good grades."
Looking back, Reynolds agrees. "I'd just be outside every day until 12 [at night]. I'd be outside playing and being rough."
Her grandmother saw an ad for Big Brothers Big Sisters on TV and knew she had to do something. "Leikia needed somebody in her life who was younger. ... I'm kind of sickly, and I couldn't get out with her a lot to take her places," she says. "I saw a need for her to have a Big Sister to show her a better life."
Reynolds was matched with Nicole Marchand, a chief assistant district attorney in Atlanta, six years ago. Marchand learned early on the importance of giving back by watching her mother mentor co-workers and other women at their church. After graduating from law school, Marchand was ready to do the same for Reynolds.
Marchand spent time with her twice a month and talked to her about making better choices.
"When you're in an environment where that's what you see, you don't know you're doing anything wrong. Leikia was reacting and behaving based on her surroundings," Marchand says. "I tried to give her a different perspective by letting her see the big picture. She was doing things and not evaluating what she did. ... I would make her answer some tough questions and give her some alternatives."
Reynolds quickly learned to walk away from fights. "When I begin getting into it with people or females, I'll call Nicole and we'll start talking about it. She'll say ignore it. Don't worry about it. Don't listen to it ... don't be feeding into that kind of stuff," she says.
Marchand also helped Reynolds turn her grades around. She sat down with her early on to work through math problems, and she encouraged her to get tutoring and get involved in activities at school.
"I was headed down the wrong path," Reynolds says. "She helped me focus on the important things in life. ... I need to focus on school. At the end of the day, all I have is school to fall back on to take care of myself."
Along with finding time to impart knowledge, Marchand tried to expose Reynolds to things she otherwise wouldn't have been exposed to. She took her to her first concert, to sporting events and even to Disney World. In 2009, when Marchand was an Atlanta Falcons cheerleader, she also encouraged Leikia to get involved in the Falcons Junior Cheerleader Program.
"It was fun to look across the field and see her," Marchand says. "I would tell all the girls on my team, 'That's my mentee right there! That's Leikia!' ... It was very special for me."
But more importantly, Marchand wanted to create a special bond.
"She's more than a Big Sister. She's like my friend, my mom, everything," Reynolds says. "I feel like if I was to start doing the wrong thing, I could call on her. Or she would probably call me first to get me back on track."
Now a junior at Tech High School, Reynolds has brought her grades up, she goes to tutorial to get help with biology, and she's the point guard on the basketball team.
"She's a very energetic young lady. She's a diligent worker on and off the court," says Brian Jones, her basketball coach and physical education teacher. "I can tell there's a sense of accountability as it relates to her Big Sister. ... She has somebody that she's looking up to that she respects very much."
Reynolds sees how far she's come and has watched other teens get pregnant, drop out of school, get into fights and even spend time in jail. She knows her life could have gone in a similar direction if she hadn't met Marchand.
"I'd probably be at Crim [an alternative school] and just probably doing bad things, being ghetto and getting into a lot of fights all the time," she says.
Instead, Reynolds has dreams of going to college and becoming a forensic pathologist. She's been on college tours with Marchand and with CREW Teens, a college and career readiness program.
If she continues on this path, Reynolds will not only be the first in her family to go to college, but the first to graduate high school.
"I have big dreams for myself," Reynolds says. "If my grandma took care of me for so long, it's time for me to return the favor. And since my dad is incarcerated, when he comes out, he'll see that I'll be the first in our family to go to college. And that I'm really doing something with my life."