OK, first I want to try and explain it for you, see GOD loves what HE created, when HE first made man and woman HE made them to live forever, and all that HE asked is for us to worship HIM and to obey HIS commandments.
What went wrong, it didn't go wrong in the Garden of Eden, it went wrong in heaven first. And the end result happen on earth. The devil that GOD created set this rebellion in motion when he questioned GODs' right to rule in heaven and man on earth, and some of the other angels listen to him. And GOD allowed this rebellion, but while they was rebelling GOD had a secret plan that HE was working on and this plan was Christ.
See Christ came to redeem us back to the Father, and He did this by becoming a sin offering for us. Christ when He died He open the way for everyone to get to the Father only if we believed Him.
Now everyone have to pass this test, the test of acceptance can you accept the fact that GOD gave His son for us. Yes The plan was for Christ to die but not us, but did Christ really died. No He can not died cause life is in Him. But He put to death sin, in a flesh and blood body. This is the true love that GOD has for us humans, we just have to accept it and keep His commandments.