Stick It, which opens in theaters Friday, is a comedy about a rebellious teenage gymnast who is sentenced to an elite gymnastics academy after she has a run-in with the law.
Stopper's friends said they were surprised at their friend's luck.
"I didn't think that [Stopper would become an actress]," Penn State gymnast Lisa Clark (senior-crime, law and justice and sociology) said. "I don't think she did either. She had what they were looking for. She was as surprised as we were."
Stick It was written and directed by Jessica Bendinger, who also wrote the teen comedy Bring It On. The film stars Missy Peregrym, Jeff Bridges, Tarah Paige and Vanessa Lengies.
"In the movie, there are four main characters, and I do the gymnastics for Mina," Stopper said. "She has blond hair, and I have naturally dark hair because I'm Italian, so they cut my hair and dyed it blond four times, once with bleach and peroxide. I also play one of the Vickerman Eight elite gymnasts."
Stopper graduated last December with a degree in rehabilitation services.
She said she began her gymnastics career at age 9 and competed as a member of the Penn State Women's Gymnastics team from 2001 to 2005.
In her senior year, she was co-captain of the team. After doing gymnastics for 13 years, Stopper said she is done now.
"I was going to be done in April 2005," she said. "It's something your body kind of looks forward to after so long, but I was like, I can do a couple more months, and I'm glad I did it."
Stopper said the experience of filming was nothing like she had expected.
"I was really nervous the first day on the set because I assumed it would be stressful and crazy, and I didn't think anyone would respect us because we weren't really actresses, but it was completely the opposite," she said. "The director came up and gave us hugs and asked us how we felt and what we thought we could do that day."
Stopper said if an acting opportunity comes up again, she will consider it, but she will not actively pursue it.
Last week in Philadelphia, Stopper said she was able to watch her own performance in the film for the first time.
"It's a lot better than I thought it would be," she said. "We filmed it backwards and shot over four hours of tape, so I didn't know what was going to be in it. It was cool seeing scenes. I think people will like it -- they did really well portraying the sport. I think a lot of gymnasts will be happy."
Stopper's former Penn State teammate, Corissa Pirkl (junior-marketing) said they laughed about Stopper's role at first.
But once she saw how Stopper was changing her body type and appearance for the role, she could tell she was really into it.
"[Stopper] went through a lot to get the part. We were all so happy for her and kind of jealous at the same time," Pirkl said.
Pirkl said Stopper still kept in touch with her friends while she was filming the movie.
"She sent us pictures and e-mails all the time," Pirkl said. "She had so much fun living in California. They got pampered, and they could order whatever they wanted. It was a cool experience for her."
Clark said she was happy her friend had the opportunity to act.
"I think [Stopper's] personality is awesome," Clark said. "She was great with the team and very outgoing. She was not passive in her position as captain; she had a strong voice. Having that personality can get a person far."
Both Clark and Pirkl said they are excited to see the film.
"We're probably going to see it as a team, and we want to see what she did, and we'll be like 'I know her'," said Clark. "It'll be interesting to see what kind of movie they make about gymnastics."