It is worth noting, however, that so far, the Aquaman previews have only shown Atlanna in scenes taking place when Arthur Curry is a child.
Depending on the DC continuity, sometimes Atlanna is dead when Arthur Curry is an adult, although in the New 52, it was revealed that she was actually alive and well, having faked her death.
Maybe that’s the case in Aquaman, or maybe something tragic happens to her early in Arthur’s life.
So in that lens, there’s no issue with age difference, but it also calls into question whether or not Atlanna will appear in Aquaman’s present day scenes.