This quote is a paradoxical statement that reflects on the concept of age and youth. It suggests that youth is not necessarily linked to the number of years one has lived, but rather to one’s state of mind and attitude towards life. At the age of sixty, according to the quote, one starts to become young, implying that it’s the age when people often start to appreciate life more, start to live it fully, and perhaps even take risks they didn’t before. However, the quote also mentions that by then, it is too late, indicating a sense of regret for not having this perspective earlier in life.

Applying this idea to today’s world, it can be seen as a reminder to live life to the fullest at any age and not wait until later years to start appreciating life and taking risks. In terms of personal development, it emphasizes the importance of maintaining a youthful spirit, curiosity, and zest for life, regardless of physical age. It could also be seen as a call to action to not delay our dreams, aspirations, or experiences until a certain age or time, as it might be "too late" in terms of lost opportunities or time.

The quote also subtly highlights the wisdom that comes with age. Often, it is only with age and experience that we understand the true value of life and the importance of living it fully. However, the irony and the tragedy lie in the fact that by the time we gain this wisdom, we have less time to apply it. Hence, the quote serves as a reminder to embrace the wisdom of age while maintaining the spirit of youth, regardless of our chronological age.