God is able to take on the big issues that seem impossible to change.
There must have been joy and relief hearing that God was going to confront the oppressors of His people, and then great shock to Moses hearing that God had chosen him to represent Him. Moses's confidence may have been humbled from his previous experiences, but self-distrust is only good if there is trust in God to be with us, strengthen us, and cover our inadequacies.
Moses's second excuse is being ignorant. It is a legitimate concern, only God can define who He is. God chose His name because of its meaning and what it reveals about Himself. Only God can define who He is.
God refers to Himself as "I" not "it" - a being who speaks, sees, plans, promises, loves, etc (versus the pagan idols that cannot act). "I am" also points to His eternal nature; there never was a time or will be one in the future where He cannot state this. Nothing can exist without Him. He is not bound by time (He speaks about the past, present, and future with authority/certainty).
God wants Moses to tell His people that the one who created Israel will be keeping promises He made to their ancestors by sending Moses to them.
God is a God who acts. He shows Moses that He has is informed and has a plan. God tells Moses that Pharaoh will reject his request. He is letting Moses know to expect conflict, and to expect victory because the battle belongs to Him.
God does not reveal Himself without reason, He is calling people to be His instruments.