John 17:
1: When Jesus had spoken these words, he lifted up his eyes to heaven and said, "Father, the hour has come; glorify thy Son that the Son may glorify thee,
2: since thou hast given him power over all flesh, to give eternal life to all whom thou hast given him.
3: And this is eternal life, that they know thee the only true God, and Jesus Christ whom thou hast sent.
4: I glorified thee on earth, having accomplished the work which thou gavest me to do;
5: and now, Father, glorify thou me in thy own presence with the glory which I had with thee before the world was made.
"I AM" is God's word for Himself. it is not merely a statement of pre-existence.
Mat 27:43 "HE TRUSTS IN GOD; LET GOD RESCUE Him now, IF HE DELIGHTS IN HIM; for He said, 'I am the Son of God.'"