If you are young in a dream means that you try to "catch the departing train," but it will be hard for you. You are thinking too much about past regrets and lost opportunities. It is time to review your plans and create your future keeping your past mistakes in your mind.
If you dream about young people, boys and girls, means that now you have the most favorable time for all undertakings. Also it may tell you that you should be more carefree and playful.