Now to answer the question as I see it
Christ is the Power the key that opened the door to salvation to enter into the kingdom of God ..The kingdom of God has always existed. It is a growing living thing. that has and will encompass all things.
Mark 4:30 And he said, Whereunto shall we liken the kingdom of God? or with what comparison shall we compare it?
4:31 [It is] like a grain of mustard seed, which, when it is sown in the earth, is less than all the seeds that be in the earth:
4:32 But when it is sown, it groweth up, and becometh greater than all herbs, and shooteth out great branches; so that the fowls of the air may lodge under the shadow of it.
However flesh and blood can not enter in to the kingdom of God
1Cr 15:50 Now this I say, brethren, that flesh and blood cannot inherit the kingdom of God; neither doth corruption inherit incorruption.
The kingdom of God is coming here physically when Christ returns but for now we can spiritually be a part of it when we accept Christ and keep our minds and hearts turned toward him