Hi Tonya,
Welcome to the Disney Parks Moms Panel! Thank you for bringing this question to us! I am always delighted to greet a fellow North Carolinian.
I am happy to learn that you are investigating the crowd intensity for the time of your visit. One of my favorite crowd calendars is with Touring Plans. In the past, I was able to access a complimentary subscription when I booked with our travel agent. Other sites also have crowd calendars. If you do a Google search for "Walt Disney World Crowd Calendar," several free options will appear. Be advised that these are not official Walt Disney World sites, but they can give you an idea of the crowd levels. For your dates, up until December 21st, the crowds could be heavy with at least a 30 minute wait on most rides. Starting December 21st and up through Christmas day, the crowds can be intense with an hour or more wait on most rides.
Unless you are planning to attend
Mickey's Very Merry Christmas Party at Magic Kingdom, I would avoid Magic Kingdom on party nights. During your visit, Mickey's Very Merry Christmas Party occurs on December 15th, 17th, 19th, and 21st. The party is unbelievably magical, so if you can attend on one evening, I suggest it! The castle shimmers, Mickey and the gang dress in their holiday finest while
festive sweets and sips tempt guests around the park. Also note that the Candlelight Processional will occur at Epcot and, depending on the celebrity narrator, the park could see larger than normal crowds.
I can imagine the joy in your little one's faces as they absorb it all!
Sending pixie dust your way Tonya knowing you will have a magical time!
-Donyell