You're the one that decides that. In my personal opinion. If you're a teenager, influences shouldn't exist in your mind. At the end of the day, it's all your decision to do what's wrong or right. Not an age restricted video of some-sort, and especially music artists.
The MPAA ratings are made by a committee in Hollywood that has set of guidelines that dictate what is considered appropriate content for viewing by younger children and teens. I have mixed feelings about this. The fear is that you don't comprehend that what you're watching is all fiction - but that kids your age won't be able to tell the difference - and may go out and act on what they've seen - usually concerning sex and violence. There's also a concern that watching films that have a lot of sex and violence in them may dull you down to what happens in real life as opposed to what happens in the movies. Generally, you should talk to your parents about this - they will have a much better idea of just how impressionable you are.
It depends what kind of restricted stuff you are talking about. If it is NC-17 then you are fine if you have consent to do that. I also refuse to believe that even in an NC-17 that you would see anything that terrible that it would warp your mind. However if you are talking about the kind of stuff that is marked as only accept able for 18+ or 21+ in some states, then yes I would suggest not watching that.