voorstellen zich can also be translated as imagine. Why can the sentence not be translated as: who do you imagine yourself (to be)??
I'd say that the 'aan wie' shows that you're doing something to (aan) someone else.
The English translation (to use your sentence structure) is: "Whom do you introduce yourself to." (Not who)
In Polish we use a phrase when a woman marries a man and a reflexive when a man marries a woman.
It is a very common mistake to use the reflexive for a woman and most people realize it only after they hear what they said. Correcting them would cause ill feeling and is unnecessary and spoils newlyweds' joy. Perfection is perfect on paper but ruins everything in colloquial and lively conversations. Be more tolerant with the little owl ;)