Paul uses an advancing analogy. He first compares going from childhood to manhood which is analogous from going to having only the OT scriptures to having the completed NT scriptures as well, then going from our position now (looking into a mirror ie. the written word) to seeing Christ face to face which, is the eternal state. The passage is dealing with how one matures and what is needed to have prominence in that process while we are learning ie faith, hope and love.
1 Corinthians 13:10
But when that which is perfect has come, then that which is in part will be done away.
The word translated perfect in v.10 is in the single neuter gender. When the same word is used referring to a person, as in Eph.4:13, Col.1:28 it is in the singular male gender. If the "perfect" is referring to Christ it should be in the singular male, it is not.
If Paul meant Christ, he could just as easily have said "when Christ comes" but he did not.
James describes the Law (Torah) as "perfect" (Jm.1:25), same word used as in 1Cor.13:10.
Do you honestly believe when we see Christ face to face that all further knowledge of Him will stop? That our relationship will not continue to grow and develop?
There is nothing you can say (prophecy) or know (knowledge) regarding Christ that cannot be found in the scriptures. What else would you use to test the spirits? Your experience? Your understanding? Of course you wouldn't, not if you are wise.
As for the gift of tongues, it was a warning gift aimed at the nation of Israel. Their Messiah had come and they (as a nation) had rejected Him. When Jerusalem fell in 70AD, there was no longer any need to warn them, this is why a different word is used for the ceasing of tongues as compared to the other two gifts. With the other two, they could fade out gradually as the written word was disseminated.
1 Corinthians 14:21
In the law it is written: “With men of other tongues and other lips I will speak to this people; And yet, for all that, they will not hear Me,” says the Lord.