Wow! In the US there are some states where you can get a learner's permit as young as 14.
Yeah, I guess America has more open/wider/quieter roads in those states that make it safer.
We have a provisional license here in the UK, which you can get as soon as you turn 17, which means you can drive, but someone who has held a license for at least 3 years must be in the car with you, and you of course need car insurance, which costs a fair bit at that point. It's far better to just get a driving instructor. lol
14 year olds driving here would be a terrible thing I think, you have to be really alert and I think a 14 year old would definitely just get themselves killed.
The UK, allow you to drive a moped at 16, a car/light motorbike at 17, a normal motorbike at 19, and any class of motorbike at 21 if you passed your motorbike test at 19, if you didn't pass it beforehand, you have to be 24 to drive powerful bikes. All of those require you to take a theoretical and practical driving test.
Heavy Goods Vehicles (weighing between 3.5-7.5 tonnes) used to have a minimum age of 21, but there's a competency test that was introduced in recent years which if you pass, you can drive an HGV at 18.
I hold a manual (stick shift I guess for Americans) car license, which allows me to drive mopeds, and vehicles weighing up to 3.5 tonnes and up to 8 passenger seats, and a tractor for agricultural purposes (apparently). Automatic or Manual transmission. I'd have to take additional tests to be able to drive quadbikes, motorcycles, LGV's, HGV's, minibuses/buses etc.
If you learn to drive in an automatic transmission car, and take your test in one, you're forbidden from driving manual transmission (stick shift) cars. Which is a problem here, as like >90% of cars are manual transmission, automatics aren't that common.