Could it be that you don’t know the truth? Truth only comes through study (2 Timothy 2:15), and it is only God’s truth that will make you free (John 8:32). Could it be that you don’t believe the truth? If so, this is very serious because God says that the only way one can gain faith is by hearing His Word (Romans 10:17). But only you can make up your mind to believe or not believe. It is a matter of choice. But to go to heaven, you must believe! I encourage you to read God’s Word and believe in His truth today.
When the truth is believed then then you can have access to heaven through obedience to God's teaching. After believing in Him, you need to repent of your sins (Acts 17:30-31; Luke 13:3), confess Jesus as being the Son of God (Acts 8:37; Matthew 10:32-33), and then be baptized for the remission (forgiveness) of sins (Acts 2:38; 22:16; 1 Peter 3:21). God created us and gave His only Son to die for us. Therefore, we now need to live for Him -- being faithful until death (Revelation 2:10). What is really keeping you from obeying the truth?