If you're interested in exploring this topic, a review of the 1921 at the ADAH would provide hard evidence for the youngest Confederate veterans from Alabama. In addition I have the student register for the University of Alabama. At my earliest opportunity I will check the 'war' classes of 1862-1865 to determine who the youngest cadets might have been.
Non Campus Mentis: World History According to College Students, is an entertaining book available at bookstores.
As best I know, no one has yet composed a book on history according to 5th graders.