Ok not the word I should have used (saved). No he wasn’t saved as we are, but he was a Holy Angel in Heaven and through disobedience was cast down. Just like we are removed from the Book of Life for unrepentant disobedience.
I believe kids are automatically saved from birth and at some point they come of age and must receive Jesus and be born again. Now that age of accountability varies from person to person, but for this exercise we will say they become accountable at 13. Now they go through life and living in unrepentant sin for the next 35 years and accept Jesus at 48. They were either not saved as kids meaning all kids go to Hell or they lost their salvation for 35 years.
I don’t think many true believers lose their Salvation, but I believe it happens. I do think that God will put all kind of road blocks up to try and stop it from happening, but he wants absolute free will by choice Souls not forced robots.
Jesus had a choice... and he chose not to sin by his own free will.
Um, Paul does not agree with your assessment that Jesus chose not to sin. Paul said Jesus could not sin because His SEED remained within Him. God cannot sin. Jesus was tempted in all ways as we are, but He could not sin because His Seed remained within Him ... the Holy Spirit remained in Jesus ...
1. Satan's similarity to us
You wrote: "...he was a Holy Angel in Heaven and through disobedience was cast down. Just like we are removed from the Book of Life for unrepentant disobedience."
The two cases are completely different and dissimilar, not "just like." Satan and the other demons were created sinless in heaven and were later cast out after rebelling. We are created sinful here, a way-station to our ultimate destination. We all rebel from the womb, from the instant of our creation ("Surely I was sinful at birth, sinful from the time my mother conceived me." Ps. 51:5). But we cannot save ourselves. God saves us by grace and, once saved, He keeps us saved. So just as we cannot save ourselves, so also we cannot "unsave" ourselves, because He is operating in and for us through His Spirit. He invests Himself in us and actively prevents us from renouncing our salvation. (I strongly encourage you to memorize Ephesians 2:8-9 and then meditate on it frequently--as often as the Spirit puts it in your conscious mind--for a year or so, allowing the Holy Spirit to embed and bring alive its vital and encouraging truth in you.)
2. Age of Accountability
I find no scriptural warrant for this strange but popular concept. As above, our spirits rebel from conception onward, and God is able to communicate even with the spirits of fetuses. Since He forces heaven upon no one, if they die in utero or as young children they still will have had the opportunity to make an informed choice of their eternal home and eternal lord.