AS is a preposition. Back in the old days the Grammar Nazis frowned on starting sentences with prepositions or conjunctions, but we've since been liberated.
I've heard people who don't know grammar very well, yet who like to dictate it (those must be the grammar Nazis everyone dreads), maintain you can't begin sentences with
conjunctions.
But you can.
I thought those who don't know soot from Shinola forbad
ending sentences with prepositions.
They don't know what they're ranting about.
Never heard the one about not
beginning a sentence with a preposition.
To hell with that!