Don’t prune it now, let it fruit …and don’t fall when attempting to harvest...

I’d cut it back in early March of next year, as John described, then fence it… until it’s beyond the immediate reach of your deer. You might also (carefully) spread the main limbs some, which could be tied off to ‘steel fence posts’ used to support protective wire… Or not. Just let it feed the root system this season, then prune while its energy’s stored below for the winter.