So your follow-up e-mail is really following up on your exchange with her back in Jan., and the e-mail is a prelude to your meeting in March to try to set up early admission to K as an option?
If I have that right, then I think I'm with you now.
If the head of admissions is interested already and has invited you for the meeting, then it doesn't seem to me that you need to do a lot of work to sell her on early admission. Doesn't her willingness to meet with you indicate that she's interested?
I guess if I were you, I'd avoid overselling DD in the e-mail. You don't want to turn her off if she's already on your DD's side. I'd just remind her of who you are and what your daughter is capable of doing (very briefly!), and request the meeting she promised, stating that you want to discuss early admission for your DD. I might even attach the Jan. e-mail exchange for her convenience.
Now, I am assuming that she's not meeting with you just to placate you and "keep you on the hook" for the following year, when your DD would normally enter K. If you suspect this might be the case, then you might need to sell your DD's special needs to her a bit more. However, I think I'd try to do that in the meeting, not in the e-mail. Such advocacy rarely goes well in an e-mail.
I had a thought: if your plan is to have DD start Hunter in the coming fall, wouldn't that be a problem if the school has already completed the admissions process for next year? That seems problematic to me.
