No, you aren't being a worrywart; young people today are under enormous pressures, and they need guidance and wisdom from those who understand the dangers they face.
Teenagers, after all, have a deep desire to be accepted by their peers. If most of their friends are going one direction, they'll want to go the same direction also, simply because they don't want to be rejected. Do all you can to help your children understand this, and encourage them to stand up for what is right, no matter what others are doing. If one of your sons ever takes the wrong road, you'll always regret it if you fail to warn them.
I suggest you also set some clear guidelines for your sons—when they must be in, how much time is to be spent on homework, etc. Watch also for any signs that they've become involved with drugs or anything else that is harmful or illegal. Let them know you love them very much—and because you love them you don't want them to get involved with anything that will hurt them.
The most important thing you can do, however, is to make Christ the center of your home. If you have never done so, ask Christ to come into your life, and then urge your children to give their lives to Him as well. The Bible says, "In him was life, and that life was the light of men" (John 1:4). Their greatest joy will come from knowing Christ and following Him.