There seem to be a lot of people on this thread who don’t really like their own children – or at least don’t want to help and respect them as they make the lengthy transition from teenager to standing on their own feet. If you’re in a position to help them adjust through their first few years of adulthood, why wouldn’t you?
Does this extend to SAHMs as well, for that matter – your husband expects you to tell him about every penny you spend on yourself and every time you buy yourself a coffee or a book – because “I only pay for the children's needs, but if you want any personal treats, you can go and earn the money yourself” ?
Does nobody just want to live as a family and support each other in whatever ways they can without obsessing about who's in charge or keeping accounts simply because they love them any more?
She needs to remember she would not be driving if you hadn’t bought her a car and paid for the insurance.
She also needs to remember that she’d have starved to death if her parents hadn’t fed her as a child and she’d have been shivering permanently if they hadn’t provided a warm house for her to live in. Does it work the other way too, when she is middle-aged and parents are elderly? Frail old Mum and Dad ask her to give them a lift and accompany them to a hospital appointment and she says “No, you need to remember that I wouldn’t have learned to drive and gained experience in the first place if I hadn’t paid for it all myself – if you want access to a car like an adult, you need to get a taxi”. Elderly parents could really use some mobility assistance such as a stair-lift or downstairs bathroom to be fitted, but they can’t afford it on their pensions. Upper-middle-aged daughter is now a successful professional and has tens of thousands in savings, but they are independent adults, so it’s not her problem or concern, right?
Obviously at 18 she is legally an adult but practically still very much your dependent child. You knew this when buying her a car/insurance. I don't think it's fair to suddenly take it away because she won't dance to your tune. It's like you are asking for respect from her but you're not showing her any in return.
This.