Interpretation of Duty lyrics?

[vampireknightzero]

Hihi everyone..I've been wondering the interpretation of Duty lyrics for some time. For instance, what is the 'it' it is refering to?? I do not understand it literally . Anyone cares to explain your interpretation of the lyrics?? Thanks!! Or did Ayu mention how her lyrics for this song came about? I love this song very much and I hope to understand it!!

Anyway below is the lyrics. (credits to http://ayumi.primenova.com/lyrics/duty.htm)

Everyone is convinced
that that "thing" they're searching
for is in the future.
But how many people have realized
that "it" is actually in the past?
I can't even guess.

I saw the end of an era
with my own eyes.
But I didn't want to know
that it's my turn next.

If, after simplifying it
a bit more, you think that "it"
merely connects and arranges memories,
then wouldn't everyone
already have "it?"
I want you to realize that.

I saw the end of an era
with my own eyes.
And in truth, I actually
do know that it's my turn next.

You'll find me, won't you?
I'm betting that
you'll find me.

I saw the end of an era
with my own eyes.
But I didn't want to know
that it's my turn next.