Congratulations on
(a) New House
(b) Prospective arrival
(c) Agreeing to have your first Christmas in your own home!!
Yes it will all be fine.
Now firstly - do you have additional storage in your new house? Particularly of the freezer kind?
(Well, actually, firstly consider Jenijena's plans!!).
But do book some internet shopping slots early, and use those to do the non-perishables and heavy stuff. Remember things like lots of loo roll and bin bags. In fact, getting an extra item each week from now on will help considerably if you can (just designate a cupboard, if you have space, or a moving box in a corner once emptied out again, as your "Christmas collection" and put those extras into it so they are not used in the meantime). Stuff like crisps, packets of biscuits, extra tea and coffee, non-alcoholic drinks, wine, beer, cleaning items, gravy mix, cranberry sauce, part-baked bread rolls, nice paper napkins - whatever you think you will need for your way of celebrating.
OK, I probably should have started with "make a list".
Are people staying in your house? Do you have enough beds or where will they sleep? Do you need bedding/towels? How many nights? (Can any bring bedding/towels with them rather than you having to change beds a lot and having loads of laundry?)
How many meals will you have to serve them? Are there any major dietary things to consider (coeliac, vegetarians, lactose intolerant, or just anyone who is plain ole picky)? Are there any things that are particularly important for Christmas to certain people (it MUST be turkey, or we ALWAYS have goose, .....etc)? Even if there are, are there any that you actually are happy to include in your house, or are there things that you want to try yourself?
What kind of Christmas dinner do you want?
What kind of buffet do you fancy?
What dishes will you need to serve things on and for people to eat off - do you have enough? (Would paper or plastic plates, to be thrown out afterwards, be useful for the buffet in particular rather than loads of washing up?)
Make a list of everything you need for every meal and for visitors in general. Remember all the accompaniments like sauces or jams or seasonings you might need.
Then, going back to an earlier point - start to tick things off as you do your regular weekly shopping from now on, especially when you see something on offer that is on your list.
Be freezer savvy.
Make mince pies or cookie dough and freeze, ready to cook or just heat through over Christmas as needed.
Put away a bag of breadcrumbs when you have leftover crusts - or even make it into stuffing now and freeze. Always useful for loads (I use it for Christmas turkey, but also mushrooms, tomatoes (with added bacon and cheese), regular chicken roasts, on sliced courgettes which are then baked, etc).
Buy things like quiches or sausage rolls if you see a deal and freeze those for the buffet.
Back to lists - is there anything that is a family special that people can bring? Or just ask them to bring something on the day like - some wine, some cheese, a desert, a large bowl of mashed potato etc.
And do a separate list where you have things that need to be done (beds made up, bathroom cleaned, bins emptied, tree decorated...etc) and see if there are any jobs that can be delegated to visitors who want to help, or DH.
A week off in advance to cook is a good idea, but I would also try to make the best use of my energies between now and then as well. So if you are making, say sausage rolls for tea one evening (I never make sausage rolls but some people love pastry making!), make a double batch and freeze the other half. The same with a lasagna that you could use for either the buffet or a meal with a smaller group over the holidays. Pasta sauces, curries, chicken and mushroom pie, smoked fish and broccoli pie, that sort of thing freezes well and can be very useful to bring out for an easy lunch/dinner when it's busy. A nice curry sauce, either frozen or in the fridge, could be a great way to use up leftover turkey for the buffet. A large batch of soup, either for starters on 25th or buffet on 26th, could also usefully be frozen ahead of time.
And then there are the veggies and potatoes for the meal itself - I know lots who freeze those too. I tend to just prep them the night before and steep them in cold water. DH should be able to help with that as well.
If you can, either book an internet shopping slot for the last few days, or go for an off-peak time. I found 10-11pm at night often reasonable in Christmas week, or 6-7am (there are a few supermarkets locally that do 24hrs at that time of year). If there is a good local butcher, that may be a great way to avoid the supermarket for the turkey or whatever, especially if you can get an internet slot for everything else.
Overall - enjoy!! You may want that week before Christmas to just relax as well.