It isn't wrong if you like it. I found myself whistling Christmas tunes last week...in JULY!!!
We usually put them up thanksgiving night at my folks...mainly because the family is all together then. My folks knock it down a day-or-three after Christmas so they can "get back to normal". I always seem to not think I was able to enjoy the Christmas stuff long enough.
At work, people were on my case for playing Christmas tunes in October. Last year I waited until November 1 but I think I'm going back to whenever the spirit strikes me this year (NOT July!).
It's hard for me as I'm whistling Christmas tunes and thinking about holidays while harvesting persimmons and processing/freezing pulp. I'm usually hitting early ripeners by mid-Sept. While harvesting I start salivating for persimmon pudding. When thinking about that, even though we eat it nearly any time of year, we HAVE to have it for Thanksgiving and Christmas at the very least. As a kid it was association with the pudding that stayed with me until today.
Sorry to stray from topic but the start of Christmas celebration is whenever you want it to be. Enjoy it!
persimmonpudding.com: dedicated to growing, education, and use of Diospyros virginiana L., the common, or American persimmon...and persimmon pudding is ALWAYS a holiday favorite!!!