Hey there

Long time WoW player here, but I'm a PvE player. So it maybe that I'll just be boring you with stuff you already know.
First off, are you familiar with WoW PvP, in general? Have you played it before on your own time? I ask because "trying out PVP instead," to me reads like you aren't familiar with it. Second, how much overall experience do you have with WoW itself, like, how long in total have you played? I ask just so I can give you better information overall.
WoW PvP, in general, isn't for the faint-hearted. It can be quite the meat grinder that can / will frustrate you. Battlegrounds are definitely where you want to start out. And, for sure, Alterac Vally as it is the most forgiving. It's a 40 vs 40 battle with PvE elements / objectives. You win the map by pushing the opposing players back into their base and defeating the boss / commander in their base.
Myself, I've dabbled in it. It can be fun. As, pretty much mostly a PvE player, I don't take it very seriously, though.