An interesting question (thanks to my friends)

[Elvish Hermit]

Next week, my literaty class is going the start "Fellowship." I never read the whole thing, but I know the basic knowledge of what's in it and what's not, ect, ect. (eg. Glorifindel, my friend. Stupid Peter Jackson)
So my friends come to me for helpful information, and in fact I started a tutoring group. I was disscussing the Nine main characters, and I got up to Aragorn, and I was saying how he was king, he loved Arwen (relating it to Romeo and Juliet)and how he had more names than a fugitive.
Then, I said that he was a child when he moved to Rivendell, and Arwen is thousands of years old.
My friend asks "Well, how old was Arwen when she first met Emeril?(she trying to be cool to get one of his newfound names right and still failing. Told her to stop watching the Cooking Channel) I was stupmed. I had no idea. We ended up having a heated debate on how old she was, that in fact she was, possibly, an adult to Aragorn and that she even helped raise him. Of course, I was unsure of any of these, therefore I said I would find out.

So I ask you: How old was Arwen, when she met Estel?