"I have a fear of driving and so I still don't drive," she admitted. "I don't have a permit."
"I'm best friends with my mom, so she kind of just takes me everywhere," she explained. "She was like, 'Bella, get a car and once you get a car you'll like want to drive and want to drive your car.' So I get a car [but] I'm perfectly content watching her drive it."
In the film, Bella's character must face her fear of open spaces when a van she is traveling en route to a treatment facility is suddenly attacked by two masked gunmen. It's a more dramatic role than we've seen from the actress, whose most recent credits include The DUFF and Blended.
As for branching out and choosing more serious roles, the former Shake It Off star said she's "lucky" to be considered for different types of characters, but explains it's not a strategic move to shed her Disney image.
"I fought for these roles, I wanted them badly and the directors and studios knew that and gave them to me," she said.
Still, she credits her breakout role on the Disney Channel series as a valuable learning experience.
"Everybody thinks that you know a Disney actor can't doing anything beside Disney. And that is not true most of the time," she said. "I don't think I have ever worked harder in my life than when I was on the Channel. It is a lot of work."
And the work won't end anytime soon! Bella, who will soon begin production on Midnight Sun opposite Patrick Shwarzenegger, revealed she may be working through her milestone 18th birthday in October.
"If I'm home I want to do a theme park -- that would be so cool," she said of her possible birthday plans. "I love theme parks and roller coasters. Although I do have a fear of heights so I don't know."
Sounds like she's got two fears to face by the time she becomes a legal adult.
Watch ET on Thursday for more of our interview with Bella. She opens up about what is off limits when it comes to her social media and also shares more about her 18th birthday plans.