The Loss of Youth And Sense - The Gain of Age and Sensibility

Sitting in McDonald's, among teenagers cramming for "A" and "O" level, makes me feels old. The loss of youth, the loss of freedom of some sort - you are more refrained and restrained somehow - that comes from within. You are not supposed to do silly things or lose your head over things like love, friends or almost any other things in your life. Being impulsive and passionate is one thing, being calm and collected is another. I may be crazy about someone, but I am supposed to be patient and composed. All these are somehow weird - we are advised to follow our heart when it comes to love, yet we are not to overreact or get over-emotional. Where is the check then? How do we balance? Sense or sensibility - I don't know which to believe.