would it be unfair for those who died earlier that are in hell?

What would really suck is dying before hell was invented and suddenly one day finding yourself in something you never knew about.

To torment a person in hell forever and ever for sinning 80 or 90 years is not fair. Why would a just, (Fair) and loving God burn people forever if they sinned for only 90 years? The bible does not teach eternal hellfire. Imperfect people teach that lie. Hell is the grave where all people ( good or bad ) go when they die.

1 John 4:8 God is love. God would NEVER torment people forever.

God never promised that anything would be fair, I mean like a man that commits evil all of his life then repents for what they had done and enters Heaven or a really generous man who gives to charity but they end up in Hell for cheating on their wife with another woman. The thing is none of us are deserving of Heaven we only are able to enter Heaven because of Jesus, so if you tried to live a good moral life and repented when you done wrong to others and helped those who needed your help you enjoy the eternal life of Heaven. If you were wicked and done things which harmed yourself and others and was hesitant to repent for what you done in some cased didn't repent for what you had done you suffer the eternal death of Hell. If God rewarded the wicked with positive punishment or He was impartial to the punishment would be unfair to those who entered Heaven by trying to obey His Law and not to mention it would be like God Himself enables sin in which it robs Him of His threats for braking His Law, in which case there might as well not even be any Law of God.

How would you know where people are in their afterlife? There is no way of knowing till you are really there. Just concern over your own behavior and the way you live your own life while your still here.

heaven and hell are not real places. They are figurative language. You could be heaven now if you are serene, peaceful, etc. ..and hell now if you are filled with hatred, depression, etc. That's why bible said kingdom of God is within you.