Why did Legolas set sail for the Grey Havens only after Aragorn's death?

[LadyBrooke]

Eldar is a hard word to define in Tolkien works. In various places, it seems to mean the elves that sailed across the sea, the elves that intended to sail regardless of whether they made it, and just a plain synonym for elf. Rereading LotR this afternoon, I was struck by a line that talked about the lifespan of the Eldar. It seemed an odd way to phrase it to me...after all, if they Eldar are only those elves that intended to sail, does that mean the Nandor and Avari have a different life span? Calaquendi and Moriquendi are much simpler...

In my opinion, blood doesn't matter, as much as what the person declares himself to be - after all, we consider the members of the Houses of Fingolfin and Finarfin to be Noldor, in spite of the fact that we know that Finarfin's children were only a quarter Noldor, and Fingolfin's couldn't have been more then three-quarters. Going back to the question of Legolas, I think it is impossible to give a definite answer on whether he was one, because we simply don't know. His family tree is very sketchy, and so is the definition if Eldar.