What was Moses' first objection to God's call?

Answer: Who am I to go to Pharaoh?

Moses first asked, "Who am I, that I should go to Pharaoh?" Later he objected that the people would not believe and he was slow of speech.

“But Moses asked God, “Who am I, that I should go to Pharaoh and bring the Israelites out of Egypt?””— Exodus 3:11 (BSB)