You can be very religious and still not know what you worship. You could be attending church your whole life and still not know Jesus. Not because you go to a church where they talk about Jesus makes you into a Christian. You may attend a church and know the rituals, practices and still not know Jesus.
Jesus himself said that at the end of times, there will be people that have a form of religion, people who thought knew Jesus or had a relationship with him. They will be shocked to find out they will not be with Jesus.