There is no set answer to this question. If you are the clear top of your congressman's slate, and other candidates on the same slate have already completed their application process, you could hear very soon that you are receiving an appointment. On the other hand, the decision could be less clear cut, where you aren't the top candidate of the slate and become part of the national pool of alternates. In that case, it is anybody's guess when you could hear back, while keeping in mind that the majority of decisions are made in the month of March, with some earlier and many later (April). How's that for a vague answer?