Qurstion about hell to Muslims and Christians?

I have been a born-again Christian for over 30 years, and felt that way at first. I have gained the understanding that God is a fair judge, and innocents are redeemed. And not just the ones who have never sinned against God (newborns!) but those who don't know about salvation and God. I believe that until all that are able have the opportunity and awareness to seek salvation, God will not return/Judgement Day ain't happening. I'm not sure how that will be achieved, but God is just.