Summary: Was it just your own choice why you believe? Could you really choose to follow God, to believe in Him, or to be saved?
"For he chose us in him before the creation of the world to be holy and blameless in his sight. In love he predestined us to be adopted as his sons through Jesus Christ, in accordance with his pleasure and will" (Ephesians 1:4-5 (quickview) , NIV).
“For HE chose…”
Others are teachings that God had given us the so-called human free will, so we have also the freedom to follow God or not, to receive or reject His Spirit, to delight in Him or despise Him.
But, is it really possible that because of our so-called freedom of choice, we are able to choose God, or even the things of God?
And we also read in Genesis 6:5 (quickview) , “The LORD saw how great man’s wickedness on the earth had become, and that every inclination of the thoughts of his heart was only evil all the time.”
With such kind of mind and heart, how can a man ever choose God?
It is not the question whether man has free will, or not. Though he has his freedom of choice, it is not enough for any man – except Jesus Christ -- to enable him to choose God and His righteousness.
As we read in 1 Corinthians 2:11 (quickview)  and 14, “For who among men knows the thoughts of a man except the man’s spirit within him? In the same way no one knows the thoughts of God except the Spirit of God… The man without the Spirit does not accept the things that come from the Spirit of God, for they are foolishness to him, and he cannot understand them, because they are spiritually discerned.”
Thus, we could only choose God, or accept His gift, if He would choose first to enable us – through His Spirit -- to understand or grasp His Worth, or the immeasurable value of His gift! For human beings are spiritually “unconscious” to behold and desire or choose what is “spiritually attractive or beneficial.”
And God “…chose US in him before the creation of the world to be holy and blameless in his sight.”
Because of the passage which says, "And he made known to us the mystery of his will according to his good pleasure, which he purposed in Christ, to be put into effect when the times will have reached their fulfillment -- to bring all things in heaven and on earth together under one head, even Christ" (Eph. 1:9-10; also Col. 1:19-20), should we believe that "all" are elected or chosen "to be holy and blameless in his sight... to be adopted as his sons through Jesus Christ" (Eph. 1:4-5)?
Should we not say that the word "all" in verse 10 of Ephesians 1 (quickview)  and Colossians 1:20 (quickview)  does not refer to everybody, otherwise we could also say that even the demons are also included?