Hi Erin!
What a wonderful milestone! I'm so happy to hear you're doing well and are ready to plan a magical celebration! AND, even better, with smart planning you may be able to attend both holiday parties. Choosing just one party is so difficult! I honestly can't decide which one is my favorite!
While the official dates for the holiday parties aren't released for 2020 yet, in recent years, the last
Mickey's Not-So-Scary Halloween Party date is November 1st. About a week later, usually around November 8th (give or take a day), the Yuletide Holiday season kicks off at Magic Kingdom with
Mickey's Very Merry Christmas Party.
It is truly a magical event to see how quickly the Magic Kingdom transforms between the Fall and Winter celebrations. It occurs almost completely in one night. Truly amazing. The other theme parks, and resort hotels, will be transformed over the first few weeks of November, but not quite as quickly as the Magic Kingdom.
I hope this helps, and be sure to stop by the Disney Parks Moms Panel again if we can help plan this important celebration!
Kathie