oldest person in middle earth

[The Might]

Tom himself said:

"Don't you know my name yet? That's the only answer. Tell me, who are you, alone, yourself and nameless?"

"Eldest, that's what I am... Tom was here before the river and the trees; Tom remembers the first raindrop and the first acorn. He made paths before the Big People, and saw the little People arriving. He was here before the Kings and the graves and the Barrow-wights. When the Elves passed westward, Tom was here already, before the seas were bent. He knew the dark under the stars when it was fearless - before the Dark Lord came from Outside."

If he said himself that his name is the only answer it clearly means that the passing of time, or of events in the outside world clearly don't affect him in his own little domain. However, he clearly is not immune to all that is of Middle-earth, as he clearly has feelings and needs.

I always thought...why does Tom Bombadil need to eat ?

But please, don't answer that, I don't want to completely turn this thread into another TB discussion.