I am worried because I cannot fix the exact day of my conversion.
That is a small thing compared with the fact that you have turned to God from you evil ways, that you have trusted Christ, and are now seeking to serve Him. It has often been remarked that Paul did not say, when writing to Timothy, ‘I know when I believed’, (though doubtless he did), but ‘I know whom I have believed’. As it has been said, I may not know exactly when I first awoke this morning, nor what awoke me, but I know I am awake. God would not have us to have faith in our conversion, but in Christ. “The wind blows where it will, and thou hearest its voice, but knowest not whence it comes and where it goes: thus is every one that is born of the Spirit” (John 3: 8). When the Spirit begins His gracious work in the soul, he does not occupy me with his work, but with my need of Christ’s work. I bow before God as a repentant sinner. My one burning desire is to have Christ, yet I feel so vile that He will not have me. I never dream at the time that all this is the fruit of an effectual work of grace in my soul; and I may in my ignorance even date my blessing from the day when I found peace; whereas the work of grace commenced on the day when the Spirit so wrought in me as to turn my soul to seek Him. In the parable of the prodigal son, the work began when ‘he came to himself’ in the far country, and said, ‘I will arise and go to my father’, not when the father was upon his neck, kissing him. It begins when soul–thirst is created, not when it is quenched.