I am with Steinspinne and Knot on this one. I don't think it reveals any deep psychological problems, its just what kids do today, but make sure its done safely. I also think its great that she asked your permission. In giving it, you have more control in being sure its done safely. Also, its not permanent, if it causes problems or she changes her mind, all she has to do is take it out. Its private, so in no way will effect how a more conservative prospective employer, etc. views her. There are worse things, so if it were me I'd pick my battles. By the way, both my kids have piercings, and they are outstanding students at outstanding colleges. I don't like it either, but I respect their right to self expression and understand that it is simply a part of our modern popular culture.