“The Dean'” really should see more of the context of your letter before weighing in responsibly. BUT … from what you’ve told me, this does NOT sound like a waitlist. It sounds, instead, as if the college will give you a decision in a little while. And that decision could be yes, no, OR waitlist (assuming, of course, that this college uses a waitlist. Not all do.)
Did the admission office ask you for more information … e.g., your most recent grades or newest test scores (if you took any additional tests recently)? It’s also possible that you are a borderline candidate and the college JUST got the mid-year report from your school counselor, so the admission folks need time to review it.
I’m just speculating here, but–from the little I know—I suspect that the college wants you to sit tight and to look for a decision in a little while. Did they give you any indication of when that would be? If not, it’s fine to write back and say something like this:
Thank you for contacting me about my admission decision. Can you give me any indication of when I might hear from you again? Is there any additional information I can send you in the meantime (e.g., latest mid-quarter grades, activity updates). I am very eager to attend [name of school] and hope that I will get good news this spring.
Obviously, if your grades have gone downhill, don’t offer to send them!
Alternatively, you can include some updates right in this message.
Since I submitted my application, I’m happy to report that my grade went from a C+ to a B in physics and I’m holding my own in calculus (my hardest subject). My community service club finished the annual bottle drive, which I organized, and we raised twice as much as we expected; I took part in my school’s Poetry Slam yesterday; and I’m now working 14 hours/week at Yogurt World not 10, as I reported on my application. If you would like additional updates about my classes and activities, please let me know.
Any time you get a confusing message from an admission office, don’t hesitate to write back or telephone to get clarification. The answer you get directly from the admission office is bound to be more accurate than the one you can from “The Dean” … at least this time. 😉