I think you are handling it correctly. As things like insurance come up, she’ll have to handle them. You can give her some suggestions like getting it from the school or contacting an insurance broker to buy it off the exchange. If she’s not getting money from you but has figured out how to get it from the trust, she’s figured it out.
I have one kid who knows where every single dime is spent. She just bought a car and financed it, and it already trying to figure out how to pay it off early. Her sister? Doesn’t even know what dimes are, or how she’ll get some to pay for things. She’s not even aware of the need for health insurance. I don’t know how to teach it except to go over everything with her step by step.