It's a sweet story but...
His trauma is going to make the concept of sex or even intimacy alien to him, for a long time, if it didn't outright turn him asexual. Being able to do this so soon after the regular adventure is just a bit rushed IMO.
Personally would've enjoyed this more had it been obvious that some more time has passed, that Goblin Slayer spent more time with his new companions, that way him interacting with Farm Girl this manner makes more sense.