So I just rolled up a character for a game (D&DD&D 3.5 if it matters)5e game and looked around table to see we had two ex-soldiers, a professional bodyguard, and a 'famous' adventurous. (A level 1 bard with a big mouth.) I'd created a young pastor of a small town. At least in my head, my character hadn't had any experience with armed violence or murder. My first thought was to rework my character to fight with the rough crowd I was about to get caught up in, but talking to the DM and the other players they seemed to really enjoy the idea of this innocent preacher getting caught up in the localized goblin genocide that your average D&D party quickly becomes. I think this could be fun as well, but I also don't want to be a drag on the cheerful lack of empathy towards koboldkind that's somewhat of a staple of our games.
How do you roleplay a first exposure to killing? How long would it take to get an otherwise normal person to get used to the way your average adventuring party behaves?