[Morthoron]

What you say is true, Inzil, but I think it's also fair to say that Arwen really didn't understand or perhaps ignored all the ramifications of mortality until Aragorn chose to die with dignity, in the manner of the earliest Numenorean kings. The immediacy of mortal death did not concern her up until that point. "Lesser" folks like the Hobbits and even Gondorions and Rohirrim may have died along the way, but Aragorn remained constant, as a man of truer blood than those around him (and he certainly aged less rapidly). Once he died, the thought of mortality hit her like a ton of bricks, and she didn't handle it gracefully.