Gef's answer is correct. Cognac only matures while it's still in oak barrels, not in the bottle. Once it's in the bottle, it's quality won't change for better or worse.
Napoleon cognacs have to be matured in oak casks for a minimum of six and a half years and are therefore regarded as being at the 'better quality' end of the market.
The Camus family are long-established producers of quality cognacs, so the bottle you've got contains a decent cognac but it'll be no better (or more valuable) than most of the bottles of Napoleon cognac which you can currently buy in Tesco.
Chris