So we can be whole or perfect even with blemishes. To be sinless is not possible for most if not all people Christ excluded. But think of it this way; we were sinless in the preexistence but chose to live an Earthly life to progress.
So we could have remained sinless for all eternity but we chose to experience the darkness so the light would have meaning, we chose to experience filth to give cleanliness meaning and joy. We chose to experience tragedy to give meaning to our triumphs. We chose to be oppressed so we would know what it means to be free.
There are experiences in this life that can only be had in this life. Everything we've been through, alone and together, shape us into being the people we were meant to be, the people we were created to be and it all hinges on our choices. We can chose to let that responsibility slide or we can chose to live up to that. Our path hinges on our choices and it was Christ who lived and died for that agency to choose.
He was not just perfect, He was blemishless. But our role in this life is not to be blemish free, it's to be made whole again. It's to be perfected in that sense.
Humanity is like one big jigsaw puzzle with each of us being one of billions of pieces that when brought together form the image of the God in whose likeness we were created. But likeness not only in appearance but in personality. We all have a purpose, some great and some small, but all are more than nessecary-we are each essential.
Our goal in coming here is to be made whole as was Christ and to progress in ways only possible in an Earthly life, and in that sense to be like Christ.
To think like Christ, to see others as He sees us, to love one another as He loves us and to love our enemies as Ge loves them and to see them as children of God helps us progress into being Christlike.
There is no end for us, existence is eternal so we will endure and progress eternally if we learn from our mistakes, our sins, and even learn from the mistakes of others.
Our path, our road is eternal. To endure we need only endure the endless revolutions from here to eternity.