Today's 16 year olds are by far not mature in thought enough to vote. Sorry no.
What about African Americans in the 1700's? Again, on average less educated and "mature" as one might say due to being a disenfranchised population.
The funniest thing about your vote, is that in 2 years from 16, they somehow magically become mature enough...
The reverse is true of black people and adult women: the more learn about the brains of these adults, the less proof we find for any differences in potential brain function.
This is why we treat the decisions of children more lightly than we do the decision of adults. This is a good thing, societally; otherwise millions of children could routinely be imprisoned for assault and battery due to common schoolyard shenanigans.