would agree if youd start in a remote village, but they all have a larva in theirs brain. so regressing isnt out of idea, and they do all have backstory, but nothing realy big(nothings like slaying goddess or things like that), making it possible that the exp they have gather was enough for them to go from ''commoner'' to ''Adventurer class lvl1'' ... no? i have mostly spam reload to try things from multiple angle so i cant say i know all theirs bg.
but i know astarion a bit and he first hide is power, then if you let him do what he want at the cutscene at the camp, he got a new attack. and since then, you are lvl 3. so its not out of range
