Yup! Its the prelude of light.
Despite not being what I say I am (its a conclude, not a prelude.)
You'll find me quite useful (Enough said)
But defeat phantom (You must beat phantom ganon to get it)
And I'll Become your passage way (Its a teleportation spell)
To the fountain of youth (When your old link, you can go to a place the sends you into the past.)
But at diffrent times, the oppisit. (seven years before that, It makes you seven years older)
Go_Dark_Link, its your turn to post a riddle.