The `Mean` hitmaker - who was named Favourite Country Singer at the People`s Choice Awards earlier this month - is often in disbelief at just how well her singing career has gone and she constantly worries something will go wrong.
She said: "This is what I`ve wanted to do my whole life. It never freaks me out. Never. Ever.
"But you know what does freak me out? When is the other shoe going to drop? I am so happy right now. So I am always living in fear. This can`t be real, right? This can`t really be my life."
The 22-year-old beauty has had a number of celebrity boyfriends in recent years - including Jake Gyllenhaal and Joe Jonas - but she is currently happy being single, though she is fully aware her celebrity status may put prospective partners off when she is ready to date again.
She added in an interview with America`s Vogue magazine: "I got nothing going on! I just don`t really feel like dating. I really have this great life right now, and I`m not sad and I`m not crying this Christmas, so I am really stoked about that.
"If a dude is threatened by the fact that I need security, if they make me feel like I am some sort of princessy diva - that`s a bad sign. I don`t have security to make myself look cool, or like I have an entourage. I have security because there`s a file of stalkers who want to take me home and chain me to a pipe in their basement."