This quote by Oliver Wendell Holmes is a funny way of expressing the concept that age is relative. It recommends that age is not a set number, however rather a subjective experience. It suggests that a person's age is determined by how they feel and how they perceive the world around them. It likewise suggests that age is not necessarily identified by the number of years one has actually lived, but rather by the experiences one has had and the knowledge one has gotten. This quote is a suggestion that age is not a constraint, however rather an opportunity to discover and grow. It motivates us to welcome our age and to maximize the time we have. It is a suggestion that age is not a barrier to living a full and significant life.
"We should so provide for old age that it may have no urgent wants of this world to absorb it from meditation on the next. It is awful to see the lean hands of dotage making a coffer of the grave"