Why I'm afraid to have teenagers

Have you noticed the state of the world lately? Kids are being bombarded from every side with pure trash and filth. My children are safe as long as they are young and only influenced by what I allow into my home, but that can only last for so long. In 4 years my oldest son is going to start school and I will no longer be in control of every thing that he is exposed to. I feel that once he starts school it will be me and my husband fighting the world for our son. The world expects and encourages teenagers to experience everything and experiment. The problem with that is many of the things they are pushed towards are addictive and dangerous. How do I help my children understand that even though the whole world says it's ok, it really isn't.