My recently diagnosed 18 yo AuDHD dd organised to be dropped off by her friend. I managed, working a lot of magic, to get her to change that and I dropped her off with the help of another friend. It should have been dh as well, however, his dad just died and he had to go back to his home country to sort the funeral etc.
It is really important not to show any negative emotions or get upset about this. Your dd will likely dig her heels in more if you do, because she doesn’t want you to make this about you. And if she does agree to you going, it’s important to register her cues as well. And not get hyacinth or emotional at all.
I am presuming you and her dad are together and / or have a good relationship. I’d team work this one. This is a rite of passage and as her mum, you would very much like to be there. You understand she’s a young woman now. And you have no intention of treading on her toes or embarrassing her. You’d just love to see where she’s going to hang out for the next year, because you love her and because it’s such an exciting time for her. Make it as much about her as possible. Keep the emphasis on staying in adult, neutral communication.
Get her dad on side to say that this is something to do as a family. This is how families do it. That if she likes, you and she can sort her room together whilst her dad does the trips to and from the car, so that she’s all unpacked and you will take the cases and boxes home with you, so that she doesn’t have to deal with them. Make it easy for her.
If she still says no, just be very matter of fact, no emotion and say you’ll be up to visit next week to check she’s settled in ok. If she then objects to that, you can shrug and say it would be far easier for you to come at drop off then. Then walk away. Let her process.
And if she still says no, don’t hold it against her. My dd absolutely tanked her 18th birthday with us. She was vile and refused to celebrate it with us at all. There is always some issue or other with dd. It’s tiring. And she will grow out of it. You just have to have endless patience unfortunately.