翅膀没长硬就别到处乱飞
[chì băng méi zhăng yìng jiù bié dào chŭ luàn fēi]
Translates to 'If your wings aren't yet strong, don’t fly around aimlessly'. This conveys caution against recklessness before being sufficiently ready or capable. Often used to advise youth to build strength before spreading their wings.