We were chosen in Him from before the foundation of the world, which is when our purpose was given to us, note 2 Timothy 1:9, but we were created in time as new creations in Christ at the time of God's choosing for us to fulfil His purposes, note Galatians 1:15-16, God chooses the time for when He reveals Christ in us. This is a very important concept as it gives meaning to our supernatural existence at the hand of God our Creator.
2 Timothy 1
8 Therefore do not be ashamed of the testimony of our Lord, nor of me His prisoner, but share with me in the sufferings for the gospel according to the power of God, 9 who has saved us and called us with a holy calling, not according to our works, but according to His own purpose and grace which was given to us in Christ Jesus before time began, 10 but has now been revealed by the appearing of our Savior Jesus Christ, who has abolished death and brought life and immortality to light through the gospel, 11 to which I was appointed a preacher, an apostle, and a teacher [c]of the Gentiles. 12 For this reason I also suffer these things; nevertheless I am not ashamed, for I know whom I have believed and am persuaded that He is able to keep what I have committed to Him until that Day.
Galatians 1
11 But I make known to you, brethren, that the gospel which was preached by me is not according to man. 12 For I neither received it from man, nor was I taught it, but it came through the revelation of Jesus Christ.
13 For you have heard of my former conduct in Judaism, how I persecuted the church of God beyond measure and tried to destroy it. 14 And I advanced in Judaism beyond many of my contemporaries in my own nation, being more exceedingly zealous for the traditions of my fathers.
15 But when it pleased God, who separated me from my mother’s womb and called me through His grace, 16 to reveal His Son in me, that I might preach Him among the Gentiles, I did not immediately confer with flesh and blood, 17 nor did I go up to Jerusalem to those who were apostles before me; but I went to Arabia, and returned again to Damascus.
And Ephesians 1
1 Paul, an apostle of Jesus Christ by the will of God,
To the saints who are in Ephesus, and faithful in Christ Jesus:
2 Grace to you and peace from God our Father and the Lord Jesus Christ.
3 Blessed be the God and Father of our Lord Jesus Christ, who has blessed us with every spiritual blessing in the heavenly places in Christ, 4 just as He chose us in Him before the foundation of the world, that we should be holy and without blame before Him in love, 5 having predestined us to adoption as sons by Jesus Christ to Himself, according to the good pleasure of His will, 6 to the praise of the glory of His grace, by which He made us accepted in the Beloved.