Holiday Schedule

My ex left a couple years ago for someone else and has made my life quite miserable since with stringing me along and making me believe there's still something there.  OK, it is what it is and now that part has passed.  Within the first month of her asking me to move out, she had me sitting in a lawyers office signing a legal separation.  Part of this agreement was holidays; ie  Christmas, Easter, and Thanksgiving.  Today I get an email from her going over this year's already agreed upon holiday schedule,  but at the very end she added a new wrinkle. 

 "New Years Eve--I've had them the past 2 so i assume you'll have them this year."  

 

Mind you, the last 2 years have never been a question, nor have they fallen on my scheduled visitation days.  This year is no different.  How do I answer her on this?  Do I take the kids or do I tell her no?