As I think, I am becoming a God!
How does it sound to native speakers?
Not entirely sure what you are trying to say, sorry.
Are you trying to say that you believe you are becoming a God? Because then I would do something like: "I think I am becoming a God!"
Or are you saying that thinking makes you more God-like? I would say something like: "By thinking I am becoming more like God"
This appears to be a fairly well-known quote from Roman Emperor Vespasian. The Romans often considered dead Emperors to be gods, and built shrines or temples to worship them. Emperor Vespasian's last words are reputed to be Vae, puto deus fio "Dear me, I think I'm becoming a god".
So to me, this seems to refer to this event, and would mean "I'm about to die."