Well they say that nowadays kids mature faster. I was a teen just yesterday... and I donot think they have matured that much as I do go to high schools to counsel from my Univ. However, they have been given more responsibilities to make their own choices that is for sure i.e. entering Univ. at 18 and deciding at 17 what program etc. to follow.
They do make other decisions but it is what they have been told is good or bad. This is not from personal experiences at times.
There is a lot of inner development that takes place for someone between the age of 18 and 21 too.
17 is really too young from my perspective.