I’m just gonna leave that here and encourage you to read it, and welcome to AD 
I started out on a PvP realm back in the days and then moved to Defias to try out rp and eventually ended up here when I realized defias wouldn’t recuperate from the realm merge, I haven’t regretted it a second. Now with the warmode you can also get that PvP if you want that.
I have only tried Horde rp once and it was on a Troll on a festive event, it was super fun though, and I think Horde can bring some nice more “primal” rp than Alliance, though Alliance has a bigger community, with the pros and cons that brings.