Continuity mistake: When Diana get the photo at the start, there's a clipboard beside the case when she opens it, but from another angle there's nothing there.
Continuity mistake: As Diana is translating in the General's office, one of the buttons on her coat is undone/missing. As she approaches his desk, it's suddenly visible on her coat where it should be.
Continuity mistake: After Diana crashes through the window, there are various bits of wooden debris on the floor in front of her. In a wider angle those bits have vanished.
Answer: It would be more accurate to say they grow to a certain age then stop aging. Similar to the elves in Tolkien's Lord of the Rings.
jimba