Violence: How much is too much?

As I continue in my writing journey traveling towards a pivotal point in the story I realize I'm going to have to write a scene of fighting/violence.  The question arises in my mind for a YA novel how much violence is too much?  Where does one draw the line?  Let me just preface this by saying I'm a conservative person, I come from a conservative background, but I wonder if by minimizing the amount of violence shown it will minimize the story itself.  I'm no stranger to violence, my current guilty pleasure is "The Walking Dead" which is riddled with zombie brains and dismembered body parts, so though I've seen it I still don't see it as an absolute necessity.  In fact, on more than one occasion while watching "Walking Dead" I've said to my husband "That was a little much."  It is hard as a writer to know where to draw the line.  In my story the main character HAS to engage in battle, bloodshed, and treachery in order to grow and accomplish the things I need her to, however I wonder can I make it interesting without making it a gore fest?  What is considered gore and what is considered necessary?  Do I let her, and the reader, hear the snapping of bone?  The warmth of spilled blood? The ultimate grief that comes from the realization that she has taken a life.  What do you think?