No one has been glorified yet but Jesus Christ. God is so confident that He can finish what He has started that He states the promise as though it is already completed.
Verse 29 says, "For whom He foreknew." "Foreknew" applies to that period before His calling of us. Before He caused us to turn to Him, before He actually extended the invitation, He knew us. He was watching over our lives. Who knows how many times He intervened to alter the course of our lives in order to bring something critical about, whether it was our education or saving us from injury or death or disease? Who knows how He may have intervened because He "foreknew" us?
My study Bible comments about the word "foreknew":
This is not simple prescience or advanced knowledge. This knowledge should also not be understood in the sense of being acquainted with, but in the sense of bringing into a special relationship with, as Adam knew Eve his wife.
In other words, foreknew does not merely mean "to be acquainted with" or "to have advanced knowledge" of us. When God foreknew us, He was so close to us that He was sticking right by our side. He had clear insight and attended closely to what was happening in our lives.
God said to Israel, "You only have I known of all the families of the earth" (Amos 3:2) Jesus said, "I know My sheep" (John 10:27). In Matthew 7:23, He said to another group of people, "I never knew you."
Foreknowledge is God's determination to bring certain ones into a special relationship with Himself. Since it is foreknowledge, He determined to bring us to glory long before He called us, long before He caused us to turn to Him. He has been personally involved with us. We were not just personally selected, but also personally sought out. Why? We could say "for glory," that is, to be admitted into His Kingdom. This is certainly true, but it was also so that, first, He could have a relationship with us, that we would seek Him.
John W. Ritenbaugh
The Holy Spirit and the Trinity (Part 7)