Very few wines improve with age, but all wines will age. 99.9% of all wines are ready to drink when you buy them and will not improve with keeping.
What happens when a wine ages is some very complex chemical reactions which cause a change in the taste of the wine. For most wines -- those 99.9% the change results in a worsening of the taste, a loss of freshness and fruit.
The remaining wines, which are intended for aging, are not very pleasant to drink when young. Their fruit characteristics are hidden under tart bitter layers of tannins (tannins taste like stewed strong black tea), the tannins come from the grape skins and wood barrels used in winemaking and they help to give longevity to the wine.
As the wine ages, the tannins soften but so does the fruit flavours fade. What we look for is that the tannins will soften before the fruit fades and the fruits will become the dominant flavour. Thats when the wine is at its peak, then the fruit will fade leaving a thin woody wine.
A lot of people do not like the flavour of aged wines -- in the UK we prefer to age wines much longer than the French will keep the same wines.
Join a tasting group where you can have the chance to taste some aged wines and make up your mind which you prefer.