Jennings insists that he’s not old

As humans go, new Viking receiver Greg Jennings is young.  As dogs go, he’s ancient.  As NFL players go, he’s somewhere in between. Either way, Jennings is definitely sensitive about the fact that he’s pushing 30. “I’m not old,” Jennings said during his introductory press conference, via NFL.com.  “I’m 29.  I’m not old.  Let me…