The first sounds a bit unnatural, but isn't necessarily incorrect, just quite stylized in terms of construction. The others strike me as incorrect. How about: You are so terribly perfect, OR You are so perfect that you scare me, OR You are so perfect that it's scary.

Hi there, The structure "to be so" + adjective + "as to" is correct English. It can be followed by a verb, either "to be" or an action verb. So your first two sentences are grammatically OK. However, "you are so perfect as to" is often used in a derogatory sense, i.e. to indicate the person identified as "you" thinks too highly of himself or herself and therefore cannot make any mistakes or can never be wrong. As for your last sentence, it is not grammatically correct. The word "in" is not appropriate here, and "terrible" is an adverb modifying "perfect" so it should be written "terribly". Therefore, your sentence should read: "You are so terribly perfect". Hope this helps.