A few facts for the mailbox stalkers . . .
Based on past history, GENERALLY, MOST offers of appointment go out in Feb. and March and thus a good number are still to be made.
Again, based on history, if you haven't heard good news by the end of March, it's less likely you'll get good news. That said, people do still receive appointment letters in early April so don't totally despair come April 1.
Everyone is supposed to hear by April 15. At that time, most who haven't heard already will be turned down. Some will be placed on the Waitlist. Very, very few receive offers of appointment on April 15 (just being honest here).
Historically, the Waitlist has not been officially "ranked." IOW, if there are 100 people on the waitlist, you won't get a number telling you where you stand and USNA says it doesn't have such an internal ranking. There is no fixed number for the Waitlist -- USNA has said it's been as high as 150 although they've never taken more than 50 off the WL.
Whether you get accepted off the Waitlist depends on the acceptance rate vs. the anticipated acceptance rate (the "yield" for the class) and that is beyond USNA's control.
There is no timetable for hearing whether you've been accepted from the Waitlist. Last year, they took almost no one and so most/all WL people got turndown letters in May. A couple of years ago, they did take some off the Waitlist but most people didn't hear either way until mid-June.
If you get a turndown letter, it is permanent. USNA won't suddenly send you a letter saying they've changed their minds. It won't help to show up in Annapolis on I-Day, hoping to take the place of someone who doesn't show up (which happens) or who quits on Day 1. So, proceed with Plan B and consider reapplying.
If you are put on the Waitlist, proceed with Plan B. Do NOT forego Plan B hoping you'll receive an appointment. If that appointment does come through, you'll have two great choices.
Good luck to all still waiting!