thats a good question pedram, honestly it doesn't matter if we are going to exist for eternity, because God isn't going to tell us (in the quran) that humans are this much behind God in eternity but rather He just says for example "i'm eternal and you are not" haha.... meaning God is there yesterday, today, and tomorrow. The difference is we weren't there in the beginning so God is farther than us, thats what it really means. Now when we are re-created and we being in heaven for forever thats not the same as God. Its really simple if you want to know the answer you have to ask yourselve were we there before God or was God there before us. Finally the question you should be asking yourself is "How will God make us eternal?" of course you will have problems but hope you get the point.