We often view God's Kingdom as something far off and away, “Heaven”, “The Sweet By-and-By”, “The Otherside”. And if we're “lucky”, when we get to the Pearly Gates, then we'll know for sure whether we're accepted or not. 
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Sounds like a dice roll to me.
 
Yet, the theme of God's Kingdom far-off is standard Christian preaching, of practice, hymnals, and understanding. Fortunately, we don't have to wait until the Pearly Gates to know. Jesus promised at the moment of baptism, His people are endued with His Spirit – His Power on High.
 
He that believeth and is baptized shall be saved;
but he that believeth not shall be damned.”
Mark 16:16

Hence, that's pretty clear. We are to believe (trust, obey, act) on the Lord Jesus Christ and be baptized.

"Then Peter said unto them, Repent, and be baptized every one of you in the name of Jesus Christ for the remission of sins, and ye shall receive the gift of the Holy Ghost."
Acts 2:38

Thus, at the moment of faith in Christ and baptism, we are “translated” into the Kingdom of Christ.

"Giving thanks unto the Father,
which hath made us meet to be partakers of the inheritance of the saints in light:
Who hath delivered us from the power of darkness,
and hath translated us into the kingdom of his dear Son:
In whom we have redemption through his blood, even the forgiveness of sins:"
Colossians 1:12-14

Thus, Christ's Kingdom exists within His people.
(Those who believe in Jesus and obey Jesus by His Spirit.)  

Notice, Jesus told Pilate His, “...Kingdom is not of this world...”

"Jesus answered, My kingdom is not of this world:
if my kingdom were of this world, then would my servants fight,
that I should not be delivered to the Jews: but now is my kingdom not from hence."
John 18:36

and the Bible says Christ believers are, “...not of the world...” either.
 
"I have given them thy word; and the world hath hated them,
because they are not of the world,
even as I am not of the world."
John 17:14

These are Christ's people. Fortunately, Repentance, is a reconcilable feature of our relationship with our King – for Jesus is the King of His Eternal Kingdom to which all true Christians are called to live in now and forever – in spirit and truth – in earth, and in heaven.

"When Christ, who is our life,
shall appear, then shall ye also appear with him in glory."
Colossians 3:4