@sammyjoanne yep, completely normal car load. I think before they do it, people massively underestimate how much stuff you actually need. We did a dummy pack to see how it would all fit in the car with 4 of us travelling too.
@Maggiethecat realistically that is a normal car load so this is what you will be buying and collecting when there. There are lots of videos on YouTube showing what people pack and loading cars up. I have a son, so no twinkly lights, no plants, nothing that I think is excessive. He has 2 blue Ikea bags of kitchen stuff not over full but it is the weight of things that make us divide it up. But he literally has 2 pans - one saucepan one frying pan, one large plate, one small plate, one bowl, cutlery is 2 of each thing. Chopping board, baking tray, measuring jug, cheese grater, bread knife, chef's knife, tupperware - several of these, 2 cups, 2 glasses. We also did an Ikea plastic tubs with herbs and spices, oven gloves too. There is other stuff too but we went through it back in early June when he came home so I can't remember everything. When you start stacking all of this between tea towels it starts to take up room.
We used 2 blue Ikea bags for the bed. The pillow took up most of one. Duvet which we left in the original packaging to keep it vacuum packed, mattress protector, sheets, duvet cover and he did take a throw for his bed. Then all bathroom stuff like bath towels (not even bath sheets like we have at home, easier to launder) tweezers, nail clippers, cleaning supplies if they have an en-suite, toiletries etc. It is a lot. Ds only took 4 pairs of shoes. That is all. Still had a full car with a large suitcase with all his clothes, underwear, pyjamas. Oh and desk stuff, pens, notepads, plus laptop etc.
Maybe an overfull cars means you can leave behind the family members who may cause arguments
We had a dummy pack about 2 weeks before going so knew it all fitted in. We had packed it early so could see how much stuff there was. Luckily Ds didn't have to empty his room over Christmas or Easter, hopefully your DD won't have to either.