Just to add, January has the potential of being very cold which can be uncomfortable for touring and make pool time unreliable. You also have some of the shortest daylight hours of the year, which translates to shorter park hours and earlier evening entertainment. Maybe not so much at the start of that date range because of the holiday crowds, but by the end at least. There also seems to be a lot of things that go down for refurbishment in January, because otherwise its a lower crowd month.
If it were me and it were my first trip, I'd postpone it for the Spring which also gives you more time for due diligence, ADRs, etc.