年轻不流氓人老珠黄悔断肠
[nián qīng bù liú máng rén lăo zhū huáng huĭ duàn cháng]
This means 'if young people are not mischievous, they may deeply regret it later on' with an added metaphor that aging leads to faded beauty. It reflects a somewhat cynical view of life stages, implying a loss of vitality or adventurous spirit over time and resultant remorse.