I main disc right now (im new to arena) im having a blast in 2s but I want to play dps now what would be a good class go get into and learn 3s with for a beginner? Thanks guys
I wouldn't advise you to go Shadow. Current meta is cleave and train priest which means you will have zero fun playing it especially because you are new. Classes that you might have fun with would be Warrior, Paladin, DK, Rogue, maybe Mage but if there is no Priest on your team you are probably the next target, but unlike priest Mage has quite a decent arsenal of tools to deal with melee.
If it's too big of a deal to level one of these then by all means go Shadow. You can get the satisfaction of playing something that is a real challenge.