This is a fun topic! I reviewed the article you linked and it references several reliable studies and is written by an author who has a doctorate in media psychology, so I would argue that she is qualified to speak on the subject. However, your claim specifies that watching xmas movies before Thanksgiving makes people happier, which communicates there is a difference from watching them after the holiday which is not mentioned at all in your article. So your claim is partially unanswered by your source because yes, they wrote that watching holiday themed movies improves mood, decreases stress, and can increase time spent with family, but they didn't say anything about celebrating the holiday before vs after Thanksgiving. I would specify your argument on that more in your next fact check!