When Christians say the Jesus is fully human and fully divine, we are saying that He really was (and is) human, and that He really always was (and is) God. Why bother? Because our salvation would not be possible otherwise. God, by His holiness and love is obligated to kill every single one of us, because we are unholy, hateful sinners. This idea that humanity in its present state is essentially "bad" (though we were originally created good in the Garden), morally unable to climb up to "goodness," and deserving only of death and judgment is not very popular. But a Christian must start with an acute awareness of the fact that they deserve hell. Yet this presents God with a dilema: He loves us and does not want to condemn us--He did not create us for that end!
The only way He could save us from death would be to die in our place. Yet another problem: God cannot die... unless of course He takes on humanity. When we say that Jesus is "the Son of God" we do not mean that God had a kid with some girl (like Zeus or some other pagan god), but that Jesus is the embodiment of God in human flesh (Colossians 2:9-10, Hebrews 1:3).
The idea that "man may become God" may indeed be an idea Christian tradition (it is definitely a Mormon idea), but I would argue it is anything but a Biblical idea. I think Moses would agree along with Paul. Dare I invoke Jesus too? Yes, He would strongly disagree with any Christian trying to become God, and instead remind him the He alone is God and no one else. Becoming "gods" is what got Adam and Eve in trouble in the first place (Genesis 3), not just bad fruit.
But remember this: God has already made us like Him, we are made in His image. This is a mystery, but true. And He certainly calls us to "be holy, for [He] the LORD your God [is] holy" Lev. 19:2. The NT affirms this standard, which none of us will ever meet, but it also affirms this: "[Abraham] believed the LORD, and he counted it to him as righteousness" (Genesis 15:6).
So you could say instead that God became man in order to make man holy like Himself. We receive our righteousness from God through trusting in the sacrifice of Jesus. If you persist in being Spiritual, as you say that is your religion, then it is like you are trying to approach God with your holiness or righteousness, and He will not accept that at judgment. I hope you follow Abraham's course instead!