He chose us in him before the foundation of the world, that we should be holy and blameless before him in love. God's decision for you did not come after your birth. It came before creation.
This means: your belonging is not a reaction to your behavior. It is a decree from eternity. Holiness here is not your task but your status. You are set apart as holy, in love.
Sonship does not begin with your decision for God. It begins with his decision for you, before all time.