YANBU. That said, we have hosted up to 40 people in our 1500 square foot home for holidays, and it CAN be done as long as you set up a plan in advance. It helps me to make a list, and to check off things as I get them done.
Certain dishes can be prepped in advance, and refrigerated until it's time for baking. Just take it out in the morning, so that it can get to room temp before it goes into the oven!
Another tip, is that YOU DO NOT need to get out all of the good China, glassware, flatware, etc...
Believe me, your family will care more about being able to be all together, than they will worrying about your place settings. Get the upgraded Chinet plates, and use the aluminum throw away pans for roasting and baking, which will keep your dishwashing to a minimum.
If they want to all be together, they won't care. Let them know that if they want to do this, that this will be the only way that you can handle it.
When we have parties (and we entertain quite a bit, anywhere from 25- 125 people!) I do ALL of the cooking, and my hubby does all of the set up-inside & outside. It just takes organization and planning. (Thank goodness the 125 person party is only once a year, lol!) It takes me almost 3 days to get it all done, but we do it, and you can too! We never allow our guests to bring anything because we just want them to have a great time. I don't even remember the last time I only hosted 15 people, lol! Good luck, and have a wonderful holiday!