Well Matured

This was a present from our Ex Daughter in Law way back in 1990. It is Plum Brandy, I think. It came from Yugoslavia as it then was.(If anyone out there speaks Serbo Croat then maybe they can translate?) She used to buy everyone bottles of Alchohol as presents. It says it was 45°, and there is still liquid in there, it sloshs! Does Plum Brandy go bad ? Should think it has a kick if it is still drinkable!