Hi Jacalyn,
Thank you so much for visiting the Disney Parks Moms Panel with your question. My traveling party is the same as yours - two adults and one 12-year-old! Let me offer you some thoughts on needing groceries in your hotel room for your upcoming trip since you will have the Disney Dining Plan.
Like you, my family typically has groceries in our hotel room. We find this helps when we want to take some bottled water to the theme parks, or grab a quick breakfast before we head out for the day. With your
Disney Dining Plan, you will receive two snacks, one quick-service meal, and one table-service meal per guest in your party per night of your stay. You will each also receive refillable mugs that you can use to get soda, coffee and so on at Walt Disney World resort hotels.
Given all of this, I would think that you likely do not need to order groceries for your room. You can use your snack credits to get snacks to bring back to keep in your hotel room if you would like, and you can always fill up your refillable mug at a Walt Disney World resort hotel. If you want to have bottled water to take into theme parks with you, or if there is a specific snack that you know you would like to have a store of in your room, then ordering groceries may be a good idea.
I hope that these thoughts are helpful for you, Jacalyn! Please do let us know if you have any further questions.