According to her Wikipedia page, she's supposed to be sixteen. She even wears her virtual hair in long pigtails. In a lot of ways, she creeps me out. I write science fiction novels, but I'm queasy at the idea of the image of a teenage girl as a saleable object. It's tad like the camel's nose in Paolo Bacigalupi's Windup Girl tent.
But I can see why Crypton Future Media, the company that created her, would see her as a good investment. She'll never get old, never get fat, and never die of a drug overdose. They call her a "vocaloid," and I'm sure they don't pay her overtime.
Here's the video on one of her concerts if you want to watch her.