We are not born as Christians.  It is something that, with God's help,  we choose to do in this life.  We can fully rely on the Words of Jesus.  If He says something, we can be assured of its truth as it is impossible for Him to tell a lie.
According to Jesus, we have only one way to heaven.  One way only.  That is by believing in Him.  We don't automatically go to heaven.  It's rather like receiving a gift - we have to receive it, open it and be blessed by it.

Here is the question - 'What is a true Christian?'  Knowing the answer to this is the most important issue in the whole of life.  This is a huge thing to say but it's true.  Making sure of our eternal destination can't have a price put on it.  Jesus says "What does it profit anyone if they gain the whole world yet lose their soul?"  He is saying that you are more valuable than all of the wealth (£70 trillion?) in the world and everything else in the world too.