I think the question of whether to put, explicitly, one's age and nationality on an academic cv is non trivial and would like the view of the community...
Up to now I have believed that (an estimation of) age can be inferred from the dates given in a candidate's Past Education (date of masters, phd, number of posdocs etc). Moreover, I have colleagues who got stuck doing multiple postdocs who were then discriminated against for their so called advanced years when applying for faculty posts ("(S)he's approaching 40 and hasn't had a faculty position yet; if they were good they would already have found a post, right?"). On the other hand, for someone who has advanced quickly, it might be an advantage to highlight that they have reached a faculty post early (or it might inadvertently highlight the young age and lesser experience of the candidate).
As for nationality, when applying abroad it can be a definite disadvantage to show the search committee that you would need migratory support to get a visa, green card etc. Or perhaps it can be advantageous to show a different background that could be brought to the post to enrich the diversity of the faculty....
As you can see, I am stuck seeing positive and negatives for both pieces of information. Is there a definitive answer or convention that one should follow?