Ha! My youngest turned 18 a couple weeks ago, and got his driver's license the same week. He was feeling very grown-up. He even had a second slice of birthday cake because "I'm an adult and it's my birthday!" I indulged him on that one, but...
He had to fill the gas on the car for the first time. It took 3 calls to his dad, but he manages.
He wanted a credit card. He was declined by the bank (not enough income--he's still in HS, only works part-time). So, I added him as an authorized user to mine. I would have done this anyway, prior to his departure for college, so he'd have access to a high credit limit if needed (stranded somewhere or something). The credit card arrived Monday, and he gleefully activated it. 20 minutes later, I get a fraud alert text on my phone. You guessed it, the very new credit card was promptly deactivated and shredded. New ones are coming.
All this happening in less than 3 weeks has really taken the wind out of his "adulting" sails. He still gets to drive himself places, including college (he's doing dual-enrollment). Luckily, his older brother only drives to/from work (Fedex, so he's home by 10am), and lets DS18 use that car the rest of the day.
I told him, being an adult isn't all it's cracked up to be.