She does however have a machine body. It's a requirement for using the biometals. Yeah, robots age in ZX, it's never really explained how it actually works...
According to the timeline, in ZX humans and reploids have started to "merge", so they've become more alike. In the timeline for the whole series, this is used to explain that by the time Legends comes along, humans and reploids have become a singularity with no differences. This renders the labeling of people as human or reploid obselete.