IMO the only real downside of waiting till 18 is that your insurance rates are gonna be sky-high for the first few years regardless of your age when that happens. If you've held a license for 2 years with no accidents then your rates are gonna be cheaper, regardless of whether you actually drove anywhere.

That's offset by teen driver education being a fucking racket though. The entire thing is just a scheme to extract a grand from mommy and daddy.

Wait till you're 18 and suddenly the need for that course and the hours of supervised driving will vanish. Pass the driving test and the written and boom, there's your license.