Lizzie Velasquez is just getting used to the endless stares. "The World's Ugliest Woman," as she was dubbed in school, is 23 years old and reportedly weighs only 58 pounds while standing 5 feet 2 inches tall.

The Texas State University senior said, "I can't gain weight," in an interview with ABC News.

Velasquez was explaining how she has a rare syndrome that blocks her body from storing fat. Even though Velasquez tries to eat as much as possible, she's just skin and bones.

"My stomach is so small that I can't eat that much," she said. "So about 30 minutes after eating, I'm ready to eat again. I snack a lot just to keep my energy up."

The cause of her condition is unknown, and only two other people in the world are known to have it, ABC News reported.

"She's missing all of her adipose tissue," said Dr. Atul Chopra, a resident in medical genetics at Baylor College of Medicine in Houston. "We just don't know why."

"Once I got to about age 13, I kind of got tired of it," said Velasquez.

"I realized I don't really want a cure for this syndrome. If a doctor found a magic pill or some surgery that would help me gain weight, I wouldn't want it. All the struggles I've had made me who I am today."

Velasquez was heavily bullied in school, and revealed that her elementary-school years were the worse.

"I felt like some sort of monster," she said, recalling her first day of kindergarten. "I never told anyone how bad I was being picked on because I was embarrassed. When I would take a bath at night, that's when I would cry."

But she didn't let the bullying get her down. Instead Velasquez wrote two books: "Be Beautiful, Be You" and "Lizzie Beautiful." Now the young woman delivers motivational speeches to young students across Texas. She even created a YouTube video titled "It Gets Better," which has had nearly 2.5 million views since she posted it in 2010.

"I tell everyone, 'Even though you don't have my syndrome, you might be able to relate to the struggles I've had,'" she said, explaining how talking about bullying is therapeutic for her, too. "It's kind of the grown-up version of my dad coming to class."

The motivational speaker says in the video, "Any form of bullying really does hurt."

She then explains that some websites even suggest that she should kill herself because of the way that she looks, but Velasquez is willing to take the bullying from strangers if she is able to stop bullying overall.