Well, I guess I'm on the right track getting an early start on Christmas!
Past research from decades ago indicate that decorating for Christmas early is in fact "good for you."
It seems these days, that the day after Halloween, all the pumpkin items are for sale, and anything related to Halloween is long gone... It seems nowadays we just jump from Halloween and straight to Christmas. However, there is some pluses on getting into the Christmas spirit and decorating early.
On the sciencedirect website, the article says "U.S. residents may use holiday decorations on their home's exterior to communicate friendliness and cohesiveness with neighbors."
This research goes back to the 1980's, it's from the December 1989 issue of Journal of Environmental Psychology. Even back then it was proven that decorating your tree could actually benefit and help your mental health, and the people around you. It also states that people who decorate for Christmas earlier, are happier, and can help others over the holidays.
So, there is in fact proof that decorating for Christmas early is good for you. I think I'm going to get started soon on getting in the festive spirit. For more info on this article, click here.