“I am the way and the truth and the life. No one comes to the Father except through me. If you really know me, you will know my Father as well. From now on, you do know him and have seen him.”
Whilst God accepts us even with our dying breath we do a great disservice to those not headed there if we say that we all go to Heaven, we need to have repented and accepted the sacrifice of Jesus to receive God's forgiveness. With God's forgiveness we enter Heaven clean, without it we would only mess up Heaven as we have Earth, and God does not allow that. What is hell? Hell is the eternal separation from God, some say it's eternal damnation, some say that we simply cease to exist, the Bible may be deliberately unclear, either way when it's most people's desire to go to Heaven when we die we don't want to hear God's words for those who haven't accepted Jesus while alive "Away from me, I never knew you." Matthew 7:23.
"My Father’s house has many rooms; if that were not so, would I have told you that I am going there to prepare a place for you?"