You are not out of your depth lovely. You can do this.
Here's what I do and it's fine every year
Get that bird in the oven at 7am. Let it cook, check it's wellbeing a few times.
Get that bird out when it's time. Cover with foil and a towel. I promise, it WILL stay warm.
Roasties - grab a ready to cook tray fro tesco/marks/wherever
Cauliflower Cheese - CHEAT. get a ready go cook tray and just add some extra cheese to the top for extra naughty - marks do big 8 people one.
Piggies in their blankets - marks have the best ones.
Stuffing - cheat, buy ready to bake
Yorkshire pud - Aunt bessies are great at
Parsnips - again, aunt bess.
Boring Veg time - girl, just grab some carrot batons and peas and shove them in the micro. If you're into sprouts get them but we don't often bother.
Gravy - you for some options here:
BISTO best - it's actually OK.
Supermarkets now do big pots of the stuff - grab 4 of those.
Or make your own... Search Mary Berry or Jamie Olivers recipes. These are how I lwarbed to make gravy.
Dessert - don't faff about, grab a yule log and a black forest from the freezers and serve.