>>718232625 (OP)
I started with Persona 3 Portable but any of the modern (3, 4, and 5) Persona games can be jumped into without the context of the previous ones.
Nocturne is also often reccomended as a starting point. As long as you abuse buffs and debuffs it's not too hard. If you play the HD Remaster be sure to either play Chronicles Mode or fork up money for Dante and play Maniax, as the original release mode isn't nearly as good.
The new Raidou Remaster is cool but it's an Action RPG instead of a Turn-Based RPG so it plays pretty differently, but it has the same themes and stuff of any other SMT.
I wouldn't reccomend touchint SMT V or V Vengeance until you finish Nocturne as those games are connected, but if you really want to you can and it will be fine.