Yet being a novice harper is entirely different from being a level 1 archmage Chosen of Mystra or the level 1 Infernal Blood War Commander of the Nine Hells, or the level 1 centuries old Vampire. I can suspend my disbelief for gameplay reasons but only so far.
But they are not presented as novice Harpers in the game. Considering it takes about one day of killing things to level up in BG1, a novice Harper would have been someone who started out yesterday, maybe a week ago. Yet they have been Harpers far longer than that, and Gorion ask them for help for a reason (unless he wanted to set up his ward with protectors as experienced as the fumbling Candlekeep assassins). Their background does not explain how they are so inexperienced in their chosen profession. This mismatch of skills vs. personal histor applies to other companions in BG1 as well. It becomes very noticeable, as you play along, that NPC levels have not much to do with their backstory, but instead with their starting location. And so the infamous Zhentarim sent an apprentice mage and a beginner rogue to try to find out who is behind the iron crisis, while Skie, the pampered noblewoman who wastes her time with Eldoth, is a master thief by the time you hire her. You might be able to suspend your disbelief on that, but I find trying to fit the levelling mechanics into BG1's story just breaks immersion. So ignore it, same as in BG3.
