Anyone can compete in any divison. Most new players and new teams start out in D4, but have the choice of any division, except pro. Some start out going straight to 7 man D3.
If your under a certain age all you need is a parents permission. This typically done at registration. The age requirements and rules are spelled out pretty clearlyin the official rule book. It can be donwloaded from the NPPL website.
I HAVE COME TO REALIZE THAT LIFES JOURNEY IS NOT TO ARRIVE AT THE GRAVE SAFELY IN A WELL PRESERVED BODY, BUT RATHER TO SKID IN SIDEWAYS, TOTALLY WORN OUT, SHOUTING ...HOLY CRAP....WHAT A RIDE !