I suppose our baby will be more like 6 weeks by Christmas (though I thought it would be older, ha) and I guess this is why we are planning on a more involved Christmas celebration at our house. It is a bit different, because DHs parents are coming here for Christmas from across the country. I have made it perfectly clear that I am not going to be involving myself much in the planning and execution of Christmas this year - I consider mothering to be my sole duty during the postpartum period, and I've decided that this includes Christmas at our house.
For us, gathering together as a family around a meal IS Christmas, so it just wouldn't happen that we would do it on our own, especially if there was family around to share it. Not just for our own sake, but also to avoid all the family drama that would ensue. So I can't offer much advice, if this is not the way it is in your family. For us, we would find ways to make that Christmas meal as hassle-free as possible while still having it, this is why I have asked my in-laws to help DH take care of it.
As a first-time mom, I know I would have found the thought of such an event to be stressful and impossible, but really you might be craving this kind of normal chaos in your life by that time. By a month you are mostly used to having a baby around, breastfeeding should be mostly working out, and many babies are starting to sleep a little longer at a stretch at night, so it's entirely possible you will feel like less of an overtired, hormonal crazy-person at that point. Or you may feel like just as much of one as ever, so I suppose it's important to stay flexible.
Good luck! Your low-key event is starting to sound better and better the more I type!