Others have mentioned planning and I agree with that in spades.
With a detailed time plan and some advanced prep (all veggies prepped the day before) you should be able to keep Christmas morning fairly stress free and have dinner on the table on time.
Do you have a partner or other family who will help? I found that by having a written time plan of what needs to be done and when means that helpers can look at it too and provide effective help. For example, I will have entries that say things like set out cheese and biscuits, set table, warm plates. Anyone willing to lend a hand can glance at the plan and see what needs doing.
When DD was a child and PILs always spent Christmas with us, Christmas morning had to accommodate:
- Get turkey in oven first thing
- Examine stocking contents
- Light breakfast for DD (but not PIL)
- 9:30 Mass
- Then breakfast for everyone (PILs very traditional and wouldn't eat before mass)
- Then open the rest of presents
- Phone other family to say Happy Christmas and thanks for pressies
- And finally finish cooking Christmas dinner to be on table by 1:30pm
Looking back it sounds frantic but, honestly, with a realistic plan and helpers it can get done.
Having said that I find it much more relaxing now nobody feel so the urge to go to church!
One other tip, which can be good but you have to time it right, put a nice shirt, top or Tshirt in a bag in the freezer about 15 minutes before you are due to serve dinner. Then, even if you get hot and bothered with the cooking, at the last minute you can slip in to something refreshingly cool just before you sit down to eat. Of course, if you leave it there too long it gets a bit stiff and you have to whack it with a wooden spoon or something and it is not such a pleasant experience