Now that stats influence the result it is not really unusual to get mastercrafts at start. As long as you pay attention who you give the jobs to or get lucky combination, at least.
I thought that attributes (creativity, spatial sense, etc) always influenced crafting.
To the OP, check your dwarfs item preferences. Matching preferences to jobs not only gives the dwarf a happy thought, but gives hidden skill bonuses. A dwarf that likes statues will create higher quality statues than they will, say, tables at the same skill level. If the dwarf also likes marble, you can get even bigger bonuses making marble statues. Combine this with random chance, an Urist can punch well above his paygrade and create a masterwork early on. Conversely, a Legendary dwarf without matching preferences isn't even guaranteed to make an exceptional item (next lowest quality). It can be rather frustrating when trying to force masterwork armor when your legendary +5 smith wants to throw 5+ duds in a row.
Oh, and masterwork items carry a whopping x12 value multiplier on them. They make excellent trade goods (just don't sell all the first ones away), and can massively boost a rooms value. This is why weapon traps are broken for increasing room value. You can stick 10 masterwork steel (edged, higher value) weapons in a trap with a masterwork mechanism. Room value will skyrocket madly from placing 11 high value (steel is worth the same as gold) masterworks in one tile. You can even -masterfully- decorate the mechanism first.