All response times from everywhere are merely guidelines, not promises - I've had places that take "a week or two" take 2 months for an acceptance, for example, and others with a "about a month" come back within 48 hours... So don't sweat it, especially over the holiday season when everyone (even editors!) are busy with real life commitments. If you haven't heard one way or another by mid January, it might be time to send a polite query.