Did Jesus die for my sin, or just for Adam's and Eve's sin?

He died for all the sins of mankind (John 1:29, 1 John 2:2).

Because we have all sinned against a perfectly holy and righteous God, we all deserve eternal separation from God in hell (Rom. 6:23). However, God loves us so much that He sent His only Son Jesus to die on the cross as our Substitute so we don't have to go to hell. Christ died for our sins, was buried, and rose from the grave three days later (1 Cor. 15:3-4). He gives eternal life freely to anyone who simply believes in Him. No one can be saved by doing good works. Salvation is by grace alone through faith alone in Christ alone (Eph. 2:8-9).

"Verily, verily, I say unto you, He that believeth on me hath everlasting life" (John 6:47).

why are you immune to Sin (or rather, Disobedience)?

Sin was "introduced" by one man (Romans 5:12). Nevertheless, "all have sinned" (Romans 3:23). Consequently, Jesus had to die for all of the sins of all of the world.

Jesus died for every sinner.

It's not likely Jesus existed at all.