It is quite impossible to make a decision to become a Christian by allowing Christ into your heart. It would actually be more possible for you to decide to become your favorite animal and begin on changing who you are to that end. Faith in Christ Jesus is a gift given to us, but before faith is given to us, a supernatural change in our hearts must take place. This is called regeneration and it is done by the Holy Spirit. If you are not saved, you have a dead soul and the supernatural change brought about by the Holy Spirit will make alive your dead soul and give you the faith required to believe in Jesus. This is why none of us can boast in our salvation…it is God’s free gift to His children.