Rowley was born in 1914 in Illinois and on January 1 she celebrated her 104th birthday.
"I'm surprised that I'm 104. It just doesn't seem like I should be that old," Theresa Rowley said, commenting on her great age in an interview with WZZM.
The woman links her longevity to Diet Coke; she drinks at least a can every day.
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"I drink it because I like it. I'm going shopping Wednesday, and I need more Diet Coke. I have a bag full of empty Diet Coke cans that I need to return to buy more Diet Coke," she added.
Diet Coke hit the shelves in the US in 1982, when Rowley was already 68. However, scientists do not believe that this beverage is able to prolong life. The CDC estimates that about one in five Americans consume diet soda on a daily basis, and it has been linked to weight gain, diabetes and heart problems.