You who are young, be happy while you are young, and let your hearts give you joy in the days of your youth. Follow the ways of your heart and whatever your eyes see, but know that for all these things God will bring you into judgment.
NIV
Rejoice, O young man, in your adolescence, and let your heart cheer you in the days of your [full-grown] youth. And walk in the ways of your heart and in the sight of your eyes, but know that for all these things God will bring you into judgment.
AMP
Rejoice, O young man, in thy youth; and let thy heart cheer thee in the days of thy youth, and walk in the ways of thine heart, and in the sight of thine eyes: but know thou, that for all these things God will bring thee into judgment.
KJV