It's a bit hard to tell from your photos, but it looks to me to be a Spheroides species, perhaps S. testudineus. Post some photos when it's a little bigger and I might stand a better chance of putting a name on it. As for the age, it is almost certainly much older than that. Most reef fishes go through a pelagic larval stage that lasts a few weeks or more before settling on the reef as juveniles. Yours looks too big to even be a newly settled juvenile. I would guess that it is a few months old.
Tony