If we want to lower the age of these things to 16, I say fine, then we can do it. The other aspect is a "jury of one's peers". It was ruled unconstitutional to for example exclude all blacks from a jury for a black defendent, based on their race, but the age peer group of the 16 year old defendent is automatically excluded from being on their jury because it is felt that 16 is too young to be able to weigh evidence maturely on a jury. There is a contradiction here.
I am very tough on crime. I think pedophiles should be shot in the back of the court room 5 minutes after the guilty verdict for example. Yet, I do believe in intellectual consistency. We treat those under 18 very different under the law. We tell them that they are not mature enough to understand many things. I disagree. We have to have an age of adulthood. We picked 18. We need to be consistent with it.