We are talking apples and oranges, I think. You are equating our past salvation, our acceptance of Jesus Christ and projecting that same salvation event into the future salvation event, entering heaven. They are NOT the same event, nor does the former guarantee the latter. When Catholics speak of "salvation", they generally are refering to heaven. THAT salvation is eternal. The salvation when we first receive Christ is freedom from the slavery of sins, redemption, being healed from sin. There is no guarantee that a person will not fall away and return to the vomit of their former life. Thus, the confusion.
Accepting Jesus as you savior ten years ago does not guarantee eternal life in heaven 10 years from now. Many will say "Lord, Lord", and Jesus will say you were not known and they will be condemned. Consider reading Matthew 7:21-24.
Regards
We agree that salvation will at some point become permanent, it is a matter of when. You are saying that eternal life does not begin until after you die. I will argue that is starts when you are born(again). Note that Matthew 7:23 the phrase "I never knew you. could indicate that there was never any provisional salvation given.
Rom.11:29 For the gifts and calling of God are without repentance.It is God who gives the gift of salvation and he knows better than to give it to someone who could not keep it.