To be honest, most adventurs start ouf at lvl 1 unless youve got a group of experiences players who moan about that fact. Then you generally starta few lvls higher if the DM is willing to meet them halfway.
But as others said its kinda plot related, the parasite reset everyone to a lower lvl essentially. That said compelte the tutorial and kill the 3 intellect devourers and you are lvl 2 so its not like you are lvl 1 for very long
