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Rachel Saintfort was always confident, so her weight — which hit 200 lbs. by the time she was in high school — didn’t really bother her.

“I was never that person who let my weight get to me,” the Lakeland, Florida native tells PEOPLE for the 2018 “How We Lost 100 Lbs.” issue. “Everyone knew me to be that girl that was big, but always took care of herself.”

But Saintfort, who says food was her “bestie,” continued to gain weight year after year. She added the “freshman 75” in college, and then more weight after she gave birth to her daughter in 2007. She also developed lymphedema in her legs, a build-up of fluid from too much salt and not enough movement.

“I panicked — I was like, ‘This is not normal,’ ” she says.

Saintfort tried losing weight and eating more healthfully, but at some point she would always give up.

“I would yo-yo,” she says. “I would always get the first 30 lbs. off, and for some reason at 30 lbs. I would mess up, and I would say, ‘Oh my god I just freaking ate a burger, it’s over. I’m just done.’ ”

But in January 2017, her daughter, now 10 years old, got in the car and said that a classmate had called Saintfort “fat.”

“She looked so sad, and she’s trying to act like it wasn’t a big deal. At that moment it hit me that she’s suffering, and she’s being picked on or laughed at because of my laziness or my unhealthy choices,” Saintfort says. “That definitely inspired me to get it together, because I didn’t want her to feel that way.”

For more on Saintfort and four more women who lost 100 lbs., pick up a copy of PEOPLE, on newsstands Friday.

The case manager decided to cut out fast food and soda — this time for good — and started doing daily 3-mile walks around the lake in her town.

“I realized that I’ve got to never quit, no matter how many times I mess up,” Saintfort says. “If I have a soda — oh well, keep it going, you’re human, you’re gonna mess up.”

She also started documenting her weight loss journey on her Instagram account, @Ms100Lbs, and set a goal to drop 100 lbs. When Saintfort hit that number less than 12 months later, she was emotional.

“I cried,” she says. “It was an amazing feeling. I still don’t feel like it’s real, but getting on a plane and putting your seatbelt on without feeling like it won’t fit, or going up a flight of steps is beautiful to me. I mean, I used to need my daughter to put on my shoes.”

Plus, Saintfort says, losing weight has strengthened her relationship with her daughter.

“To have your own child be proud of you is a feeling you can’t explain,” she says. “It’s so amazing, and I was able to show her that if you set a goal you can achieve it — you just have to keep fighting.”