Interlinear 17:5 - And now glorify Me You, Father, with Yourself, with glory which (insofar) held before the world existed, with You.
Jesus is not literally in that picture, the Father alone was holding this glory, before the World existed with him. He see things not yet done and though they are.
No Greek word exist to add the word "I" as in "I held", but never the less, let say it is "I held" and let the Bible address it to show it's correct context and meaning.
2 Tim 1:9 - who has saved us and called us with a holy calling, not according to our works, but according to His own purpose and grace which was given to us in Christ Jesus before time eternal. (The future Jesus to be).
These people here Mr G can rightfully ask the Father -> And now glorify Me You, Father, with Yourself, with glory which I held before the world existed, with You. You cannot deny this and maintain truth, and they like Jesus were not there, literally.
Rom 4:17 - (as it is written, “I have made you a father of many nations” ) in the presence of Him whom he believed—God, who gives life to the dead and calls those things which do not exist as though they did;
We need to be careful Mr G, to Not let our set seeds do the interpretations and miss the true message. It is easy to do, hence we need to be constantly on guard and keep the Bibles overall theme in mind, so you know immediately, if something is adrift, or we are reading something wrong.
A good example of that is your quote and use of John 3:13 in your other post, you left out the before and after verses, which tells/shows a whole different message.
