No one is suggesting that in order to be truly saved, one must "pass a theology exam," demonstrating complete mastery of Calvinism.

The elect are brought to the truth and acted upon by the Spirit of God, who applies the finished work of Christ to their hearts, which eventually reaches their minds as they seek Him through His word.

At first the gospel is terrifying, as it should be. Before one is forgiven, adopted, justified, etc., one is condemned and terrified of what they need to be saved from (total depravity, guilt, the justice of a thrice-holy God who is unapproachable by sinful, fallen, depraved, guilty, filthy sinners).

The gospel is humbling and even more terrifying when one realizes that there is nothing that can be humanly done to wipe out the sinner's insurmountable debt, much less make him a better person. He is not only guilty, condemned, and doomed to be the object of God's holy wrath, but he is helpless to do anything about it on his own. Nothing he can do will earn him any merit at all, much less enough merit to pay his debt of sin. If he is to ever be forgiven and have any hope at all, it must be entirely by means outside of himself and his own efforts. There is nothing I can do to deserve His mercy. It must be unconditional, since I am totally depraved.

The gospel is bad news to sinners before it becomes good news to those who are regenerated with ability to believe it and stake their lives on it.

Only the regenerate believe, and cannot say no to Christ, even though the demands of the gospel are impossible ("who then can be saved?").

Suffice it to say that even if one doesn't understand all the theology, a true convert experiences the terror, the dread, the brokenness, and the humility of desperate need and helplessness - and then the gratitude, rest, trust, confidence, and ongoing humility, obedience, and thankfulness as the Spirit applies the gospel to their hearts.

Don't misunderstand "Calvinism is the gospel" as though all the elect somehow qualify by passing some sort of theology exam. Salvation is from God and in the heart long before it reaches the mind. But the truly elect will seek to understand the gospel, and most of us find our way to "the Reformed faith" on our own, from the Scriptures themselves.