I agree almost entirely with these choices, just two things;
A) Fullmetal Alchemist might be a little too much for 12 years old, as there is a hell of alot of gore in it, not to mention the whole origin of “truth” scenes.
B) Neon Genesis Evangelion(manga) is not what you want to be using to introduce yourself to manga. It’s good, but insanely graphic and deep in a very morbid way. You could try Fullmetal Alchemist, or Fullmetal Panic for that matter.
I would also look into One Piece, or the ultimate classic; Dragon Ball. One Piece is supposed to be a lot better in the manga than in the American amine, and Dragon Ball is slightly perverse, but in a much more harmless way than most manga.