Any 'reserva' Rioja has to be several years old because, to bear that label, it has to have been aged in barrels for at least one year, followed by a further two years (minimum) ageing in the bottle.
That's a reasonable quality wine (of the type that you get through decent wine clubs) and should be delicious. The only exception might be if it's got a cork stopper which has been allowed to dry out (through the bottle being stored upright rather than on its side). Under those circumstances air might have got into the wine, leaving it 'corked' and like vinegar.
Chris