I'm confused, how can Jesus be God ?

Even Adam knew of Jesus" coming. I understand your question as I have been there. The "first" man and the "perfect" man are different by default. Rather metaphorically, or literally, the truth is the same. God CREATED both. One from dirt and one through divine conception. One showed who we are and the other what we should be. Jesus was said to have flesh like us, but WE were born of sin unlike him...or Adam who chose sin. Adam did not murder, but he did go against God before Cain did. Like Cain and Able, Jesus and Adam reperesent a duality in my opinion. The first and the chosen.