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Before JJ Aldrich was old enough to walk, her mother would carry her on her back through the roughest parts of downtown Denver.

It was the fall of 1992, and two-month-old Aldrich, her mom and three-year-old sister were living at a homeless shelter in Denver's Five Points neighborhood. Aldrich's father had gone to prison before she was born, and the family member her mom had been staying with had recently asked them to move out.

As a single parent, Aldrich's mom didn't have much money. She couldn't afford an apartment or a car, so everywhere they had to go, they walked.

Aldrich was too young to remember these times, but she's seen the pictures and heard the stories. Two-and-a-half decades later, if you ask her about her childhood, it's one of the first images she conjures: Her mom carrying her to the grocery store, spending what little they had on food and supplies; then trudging back to the shelter, leading her toddler with one hand, carrying her groceries with the other and lugging baby JJ on her back.

Just the three of them against the world.

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"She did everything she possibly could for us," Aldrich tells Bleacher Report. "She did it all by herself for years. She didn't have any other family helping her out. She didn't have friends that she would trust us with. It was just her raising us. My mom is my biggest inspiration, just as far as fighting every day and making it through, even if it doesn't seem like tomorrow is going to be a great day."

Now 25, much has changed for Aldrich, though that fighting spirit forms the backbone of her professional life.

As a pro MMA fighter with a 6-2 record, she competes in the UFC's strawweight division. This Saturday at UFC 227 in Los Angeles, she takes on Polyana Viana in a bout that will appear on the event's main pay-per-view card. A victory would give Aldrich three straight inside the Octagon, perhaps vaulting her into the organization's official rankings and cementing her as a contender at 115 pounds.

That makes the Viana fight the biggest step yet in a martial arts journey that began when Alrdich's mother started taking her to taekwondo classes when she was nine.

By then, her mom had started her own childcare business and worked her family out of the shelter and into their own place. Still, she didn't have the money to pay for Aldrich and her sister to go to one of Denver's big martial arts academies. Instead, they started training at a local rec center, where classes cost just $5 a month.

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These were formative times for Aldrich as an athlete. She remembers going to taekwondo tournaments where it seemed to her the bigger, more affluent schools had brought along 100 people. Meanwhile, it was usually just her, there by herself, getting ready to fight.

"It was hard at times, but I think the struggle made me love it more," she says. "I wasn't just given everything. I think it made me better."

By 13, she'd earned her black belt. That same year, one of her taekwondo instructors began taking her to a local MMA gym. Aldrich says she started training in the mixed-rules sport just for fun, but she soon knew that her future as a fighter would be in the cage.

"She was really raw, but she was really tough," says Tony Basile, owner of Denver's 303 Training Center, where Aldrich still trains. "She was in the gym almost every day in 2010 [and] 2011. She was always at practice, holding down the fort. Just one of the toughest homegrown girls I've ever been around. One of the best students of all time. She's just a soldier."

Just before she turned 18, Aldrich began trying her hand at some amateur MMA fights. In Colorado, however, she says there weren't a lot of opportunities to get quality matchups against people her own size. Instead, Aldrich became a road warrior, taking fights wherever she could find them.

When fighting in someone else's backyard, Aldrich says, at least she knew her opponent would show up.

"Her amateur career was phenomenal," Basile says. "She took a belt in South Carolina. She went out and took a belt in Destiny MMA out in Hawaii, which is hard to do. To go to Hawaii and take the belt from one of their champs? So, we knew we had something really special."

Working out at 303 Training Center has also given Aldrich the chance to train alongside current UFC strawweight champ Rose Namajunas. As one of Namajunas' primary sparring partners over the last few years, Aldrich had a front-row seat to her teammate's progress from contender to titlist.

"It's really cool to see somebody work so hard and get to the next level," Aldrich says. "It's been great to see that you can do it, that it's not that far away."

With Basile, Namajunas, former UFC fighter Pat Barry and boxing coach Mike Gonzales (who is also her fiance) as her primary partners and trainers, Aldrich has honed a hard-nosed, southpaw striking style. It has its roots in her rec-center past but is fully evolved for the modern MMA game.

Aldrich is also a brown belt in Brazilian jiu-jitsu under Basile, which makes her a well-rounded threat, wherever a fight may go. Each of her UFC fights has gone the distance, but as an amateur she won four fights by submission and two by TKO.

Until recently, another of her roles at 303 Training Center has been teaching children's martial arts classes, both in the gym and as part of a local after-school program. Though she's recently had to give up teaching to focus on her own career, she says being a martial arts instructor is something she'll return to when her fighting days are done.

"I love teaching kids; it's one of my passions …," she says. "I just remember being a kid and not always having the greatest opportunities. Remembering how much martial arts meant to me when I was little, if I can give that back to kids in any kind of way, it makes me happy."

Aldrich's own big break came when she was cast on season 23 of The Ultimate Fighter during the spring of 2016. After winning a preliminary fight to earn a spot on the show, Aldrich was the first overall pick of then-115-pound titlist Joanna Jedrzejczyk but lost to eventual season champion Tatiana Suarez in her next fight.

Worse, Aldrich didn't score a fight on the season's live finale and had to return to the independent circuit instead of punching her ticket into the UFC.

"It was kind of heartbreaking; I'm not going to lie," she says. "It was kind of depressing at first, but I have such a good team around me. They just picked me up and said, 'Hey, we have to stay ready. Stay ready at all times.'"

After two more wins in smaller promotions, UFC matchmakers indeed came calling for a fight against Juliana Lima in December 2016. Aldrich lost that bout to Lima but followed it up with two straight UFC wins and now finds herself on PPV for the first time, taking on Viana in a fight that could be the breakout opportunity for both competitors.

She's going off a bit more than a 2-1 underdog, according to OddsShark, but Aldrich has faced longer odds before.

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Since getting the call from the UFC, she's been supporting herself as a full-time fighter, having left her most recent job working at a factory in the Denver area. She has nearly reached the point where she can support herself and her future family with Gonzales the way she wants.

Aldrich's father is out of prison, and while the two have never met each other in real life, they are back on speaking terms. After a falling out with her mother, she is also working each day to rebuild that relationship.

Aldrich is proud of everything she's accomplished, though she's not quite where she wants to be just yet. All the struggle and hard work has led her here. Now, she says she can't wait to see what's next.

"It was really hard. I feel like a lot of people didn't want to give me a chance," Aldrich says. "I think I've overcome a lot of adversity. I still have a long way to go, of course. I'm still growing every single day."