What does it mean to be born in youth and die in youth?

"Born in youth, died in youth" is generally used to describe the transience of some people or things. It means that some people or things only exist and flourish when they are young, and their brilliance and vitality will gradually fade with time. This sentence also implies that youth is the most precious and fulfilling time in life, and people should make full use of this time to pursue their ideals and dreams and make their lives more substantial and meaningful.