No matter what other people say, a willingful person always sticks to his chosen direction. The terrible thing is not having one's own mind. For instance, some people bought Java books 2 years ago and downloaded C# and .NET 5 month ago and now change their direction to the network security after reading these discussions.
But I have to say that the market demand for the network security expert is not very large. It is very difficult for a novice to get a first job offer. An experienced network guy is not hot in the market.