Lordship begins at Salvation.

Romans 10:9 That if you confess with your mouth, "Jesus is Lord," and believe in your heart that God raised him from the dead, you will be saved. 1 Corinthians 12:3 Therefore I tell you that no one who is speaking by the Spirit of God says, "Jesus be cursed," and no one can say, "Jesus is Lord," except by the Holy Spirit. This is why Jesus talks about discipleship. Remember the story about the rich ruler? Jesus looked after the rich young ruler as he walked away, but Jesus did not follow him or attempt to coerce him. Jesus wants people make their own moral choices; and Christ knew this and permitted rich ruler to go his own chosen way. Jesus is saying that He cannot do our repenting for us. He died for our sins, now it is up to us to pick up the cross. "Salvation is free, ... but discipleship will cost you your life." (Dietrich Bonhoeffer)