I'm going to say it's too young since here in the UK alot of teenagers seem to just grow up when they hit 17 and go to college/6th form (granted theres still some idiots out there).
I passed my test when i was 17 with only 30 hours training + 6 hours for pass plus qualification (the average is 39 hours without the pass plus hours, pass plus is designed to teach you more and bring down insurance prices), within my first year i had been in one accident (a 25year old nurse slammed into the back of my stationary car waiting to turn right, needless to say her boyfriends new Audi and my 10yr old car were written off) so i guess i added to the statistic there but otherwise i've never been pulled over by the police, never been caught by a speed camera, never had anyone beep there horn at me so i would say i am a pretty safe driver (it will be 3 year since i passed my test next month). It's the same story with one of my housemates, but then theres my other housemate whose been in 2 crashes both her fault, been pulled over by the police twice (for using her phone), and caught by a speed camera, it's all about the person really, shes not irresponsible (except for the phone bit), she's actually gotten a lot better since she got her new car but she still scares the shit out of me and my other housemate if she drives sometimes.
Either way theres good drivers, and then theres bad drivers, the majority are bad, young drivers and older drivers (50+) are usually who are bad, the young for well being young, and stupidly trying to show off, then theres the old who had a driving test which was alot easier and different to the one we have now a days (e.g. my dad was always taught to stay below the speed limit, he drives 50mph in 60's etc. where as i was taught to stick to the speed limit so i don't cause congestion e.g. do 70 in a 70, NOT over but do 70, you even get minors for being to slow in the driving test in the UK).