It also seems to me that, with some notable exceptions, the mental maturity and wisdom of Elves doesn't continue to grow greater and greater with their many years. Some act just as "baseborn" as any Man even when they have thousands of years behind them. As many humans reach a certain point in life and then just stop there in terms of their maturity -- how many of us know people who are still mentally stuck in high school or college, or even elementary school? -- so do some Elves. The ones who go around talking freely about their own greater wisdom and knowledge to "lesser" races are probably about as emotionally mature as a teenager of that so-called lesser race. Arwen may have had the opportunity to see and do and learn more than Aragorn because she had more years behind her, but did she avail herself of it to any great extent? Galadriel went out into the world, sought out new experiences, learned many things, made the most of the opportunities her naturally long life could present, but did Arwen? If she did, I don't recall Tolkien ever mentioning it.
And I think one must also consider that Aragorn spent many of his formative years living in the same house and environment that had been Arwen's in her childhood. That probably made a difference as well.
Arwen the cougar, though. What a thought.
