old dogs will not learn new tricks or you can't teach an old dog new tricks. People in old age do not readily conform to new ways.

This is a canard. Old dogs and old people can learn new things. In the earliest form I could find references for this phrase, William Camden, an Elizabethan historian, offered a milder bit of wisdom in 1605: “It is hard to teach an old dog tricks.” Since he was documenting the folklore of Britannia at the time, we can assume that he was not the originator.

The difference between “you can't teach...” and “it is hard to teach....” is critical here. Presumptions of a decline in cognitive function, the key ingredient in acquiring new knowledge or learning new behaviors, is often matched in a self-fulfilling prophecy. However, studies show that for both dogs and humans, such a decline is unnecessary. In a two-year study of aged beagles, a combination of good nutrition and “behavioral enrichment” were shown to slow and in some cases reverse cognitive decline.

So, while there is a grain of truth in the adage, there is no reason to let it apply to you. Indeed, the phrase “to be an old dog” is sometimes used to mean to be experienced at or knowledgeable about something.