No, she's a fake. I don't know if she's a guy, or if she's in her 30s or anything like that..but she's not a sixteen year old girl. Not anymore. The math just doesn't add up.
In fact, the only way she could be on the up and up is if cystic fibrosis somehow causes you to age but one year for every 2 or 3 the rest of us mortals experience.
Whatever she is, she has serious problems.