I believe you are right. (Context is everything.)
My study bible confirms it.
Footnotes on Heb 6:4-6; This passage does not teach that one can lose his salvation through disbelief or apostasy. These verses refer to a hypotherical situation whereby the author stresses what would happen to a saved person if he ‘could’ fall away. The author does not believe one can lose his salvation, or that his readers had (v-9); but he so speaks to demonstrate the folly some might have in imaganing that they can turn back to Judaism without loss.
[Greek grammar paragraph on 4th and 5th participles.]
The important point about Hebrews 6 is that it agrees with the general tenor of Scripture concerning the security of the born-again believer. One basis for the securityof the believer involves the promises recorded in God’s Word (vv 18-20; 7:24, 25; 8:12; 10:10-14; John 10:28-30; Rom 8:28-39; Eph1:13, 14; 4:30; Phil 1:6; John 5:13) Yet, an even stronger basis for security is found within the nature of the new life God gives. Though conversion involves man’s will, it is God’s will that produces regeneration (John 1:13) Thus, salvation is infinatly more than a decision that one can make and then break. It is the work of God that transforms one from darkness to light (1 Cor 4:4; Col 1:13), from death to life (John 5:24), from a child of the Devil to a son of God (Rom 8:14-17). It is a completed, regenerating work (10:14; Eph 2:8 — “You are saved,” or “You have been saved and stand saved” — Greek perfect tense).
Agreed.
If God saved you (His work), then you cannot unsave yourself (your work).
Is it possible that another person's study bible, edited by a different group of theologians and interpreters, would confirm the opposing argument? And, if so, are you not just choosing one group of experts over another group of experts, all the while acknowledging that you do not have the expertise to judge which set of experts is most reliable?
Selah