agency and salvation

in mosiah 3:18, "salvation was, and is, and is to come . . . through the atoning blood of Christ",
it stated that jesus christ is the central of the plan of salvation.

last night i learned about the agency.
1/ power to choose
2/ opposition
3/ law
4/ knowledge of good and evil

these things came form the fall of adam.
since we have the agency, it brings along freedom and captivity.
if we choose the right, we are free of guilt,
but captivity brings us the lost of the Spirit.

salvation is something personal, requires our efforts.
D&C 45:58, "children shall grow up without sin unto salvation",
we can bring our own salvations, it really depends on how we use our agency.