It would appear that, soon after the death of Jesus, some of the followers of Jesus got a bit over-excited and decided that Jesus must have been God. It seems that there is always a danger of over-zealous adherents going too far in any cause .
Jesus does a lot of stuff in the Gospels that indicates that he is not the same as God. One of the main things is that he prays a lot - why would he need to pray to himself? That would be silly. That wouldn't really even be praying, it would just be thinking about stuff.
Also, when Jesus teaches his followers to pray, he teaches them to pray to their "Father" who is in heaven. He doesn't tell them to pray to the "Father" and also pray to himself, (Jesus). He tells them to ask for things in his name, but not to actually pray directly to him.
In Christianity, it appears that the central and most important belief is the divinity of Jesus. Many Christians claim that you cannot get into heaven if you do not believe that Jesus died for your sins.
However, if this is true, why didn't Jesus preach the message that people needed to believe that he was God and worship him? Jesus gave a lot of public sermons, but none of them contained anything about people having to worship him as God. If worshiping Jesus was so extremely important, he probably should have mentioned it more often.
In the Bible, the only times Jesus supposedly said anything like that would have been in small, private conversations. Of course, if you are going to claim Jesus said something that he didn't, you would have to claim he said it in private. If you claimed he said it during his sermons to the multitudes, you would have a multitude of eye-witnesses saying that you are a liar. So, if his over-zealous followers were going to make up statements like this, they would have had to claim that it was supposed to be some sort of "secret".
After Jesus had gone all over the place preaching without ever once mentioning that people should be worshiping him, it seems like telling his apostles to go around preaching that after he was gone would be rather cruel.
It would be sort of like Jesus saying, "Oops, I forgot to tell everyone the most important and unbelievable thing about myself, but I don't have time to go and tell them now, because I have to go get crucified. So, you guys make sure to tell everyone all about my being God after I'm gone, OK?"
If I had been an apostle and Jesus had said something like that, I would have been pretty upset. It would have been really inconsiderate of Jesus to do something like that.