What a heavy, sad burden you've been bearing since you were 16! You were so young! You must think of that baby every day. And now you wonder what is awaiting you in the next life.
First of all, trust not only in God's justice, but trust also in His love! The fact that you can admit that what you did was wrong shows that you are open to receiving God's mercy. In God's eyes we are all sinful. "For whoever keeps the whole law and yet stumbles at just one point is guilty of breaking all of it." (James 2:10, NIV)
Back in the Garden of Eden, God warned Adam that the penalty for disobedience would be death, the footnote in the KJV reading, "dying thou shalt die." (Genesis 2:17) Other texts in the Bible verify this truth: "for dust thou art, and unto dust shalt thou return" (Genesis 3:19); "for the wages of sin is death." (Romans 6:23) The Bible defines death as a state of unconsciousness. "For the living know that they shall die: but the dead know not anything," and "for in death there is no remembrance of thee: in the grave who shall give thee thanks?" (Ecclesiastes 9:5 and Psalm 6:5)
If it weren't for God's love, we would all face eternal death. God is completely just, but he is also all-loving and has "sent his Son as an atoning sacrifice for our sins." (I John 4:10) Jesus died in Adam's place to satisfy justice, so that we, as Adam's offspring, may all live again at the "resurrection of the dead, both of the just and unjust." (Acts 24:15) The time of the resurrection will happen during Christ's kingdom on earth, often pictured as a "mountain" in the scriptures. "They shall not hurt nor destroy in all my holy mountain: for the earth shall be full of the knowledge of the LORD, as the waters cover the sea." (Isaiah 11:9) All people will come to know God. "…For when thy judgments are in the earth, the inhabitants of the world will learn righteousness." (Isa. 26:9)
But even now, in this age, we can learn to know and love God. When we are truly sorry for our sins, we can come to Him through His Son Jesus. "If we confess our sins, he is faithful and just and will forgive us our sins and purify us from all unrighteousness." (I John 1:9) We can even experience "newness of life" (Rom. 6:4), if we decide to give Him our hearts and follow Him where He leads, though the way be difficult. May God help you to trust in His love.