I have been thinking about the verse for a while, and have read many translations. The most commonly quoted version is the King James Version:
For now we see through a glass, darkly; but then face to face: now I know in part; but then shall I know even as also I am known.1 Corinthians 13:12
Other translations do not use the word glass, but instead use mirror.
For now we see only a reflection as in a mirror; then we shall see face to face. Now I know in part; then I shall know fully, even as I am fully known.1 Corinthians 13:12
Admittedly, the glass translation is more attractive as prose, but the mirror translation is more accurate.
The verse is talking about fully seeing (understanding) what we are, once we have passed on. The second part of the verse is what dictates the correct translation (or interpretation) of the first. The verse closes with:
…but then shall I know even as also I am known.
This part of the verse indicates that there is someone that knows us better than we know ourselves, “…as also I am known”.
My reading is that once we have passed onto be with our Father in Heaven, we shall know ourselves as he knows us. With this understanding, the first sentence of the verse has to be referring to a mirror and not glass. When looking into a dark/murky image of a mirror we cannot see ourselves clearly. But when we come face to face with God, we shall be able to see everything clearly, including our own true nature.