If you do open it I suggest it's decanted - you can do this through a paper coffee filter - as it willrobably have lots of sediment. It will probably have to be drunk fairly quickly after opening as it will not have the strength to survive long when exposed to the air. I had a 30 year old bottle I decanted 3hrs before drinking and it was awful, my mate subsequently told me old port should be drunk fairly quickly.
I believe Port was created to satisfy the English tastes, some of he famous wines of Bordeaux were created forthe English and when due to wars between France and England the supply was interrupted the English turned to Portugal and Port
When you open it taste and smell it regularly to see how it develops after beng exposed to the air. It should go well with the cheese but try the wine first and the cheese sparingly to begin with, it would be a shame to over power it if it does turn out to be weak (eg a little watery)
Good luck and enjoy the experience