Citizens who are adults have the right to vote.
Citizens who are not adults have never had the right to vote in this country so they never have had those "rights" restricted.
You cite the 26 the Amendment. You do realize that the 26th Amendment LOWERED the voting age from 21 and did not RAISE the voting age from one of childhood don't you? The 26th Amendment expanded the franchise by lowering the accepted age of adulthood for this purpose. It works against you not for you.
I must say that i have never come up against someone in an otherwise intelligent discussion who clung to an ideological fiction born from their own mind in the face of all common sense and fact as you are doing here. Scratch that .... I did on another site dedicated to the works of an author and come to think of it that poster had much the same name you did except for a couple of letters in the last three. This is eerie.