Not knowing where you are some of this may not seem to make sense. But in my little corner, well not that little, of the world. The educational system is a failure. The students are not prepared for the world. When I went through school national history, as well as world, was taught. And there were classes on Civics. I also used to rail against a test I had to take as a condition of Graduation from, the same subject test, elementary, high school and college. A test on the Constitution, It felt like taking a loyalty test. Maybe that is why Civics isn't taught anymore?
But back to the subject at hand. I would be against lowering the age to 16. Primarily as these children do not have a basic understanding of the origins of the country, the mechanisms by which it works, or the discipline to consider all aspects of a decision.
All through school they have not been held to a disciplined approach of work. Under these circumstances i am not even sure that 18 year olds are qualified to vote. Though they are expected to make their own decisions as a functioning adult.