Shouldn't Fukayama already be centuries old? He looks like a fully grown dragon, more or less. Dragon growing up in a facility seems exceedingly strange. But that brings me to my second point: it's certainly easier to see this working, like this, with an Eastern dragon, as opposed to a Western one. They are quite different kinds of creatures in mythology. So, aside from the age issue, an Eastern dragon managing to grow up in a facility sounds a bit more plausible than a Western dragon.
Naturally every author has the right to make dragons whatever they want to in their own work, but is it still a dragon if you change it too much? East or West, dragons ought to be creatures that live for a long, long time if not eternally, and are large. Growing up as fast as a human seems unlikely.