Though it may seem to say he physically had this glory that isn’t the case because he had not yet recieved it.
John 17: 5 Now, Father, glorify Me together with Yourself, with the glory which I had with You before the world was.
BTW, no textual variant: http://openscriptures.org/prototypes/manuscript-comparator/?passage=john+17%3A5&view=parallel&strongs=1
God always is. For us there is time, that isn’t so with God, He created time for us. This glory that was Messiah’s existed before the existence of the world in the mind of God.
That would make Yeshua a thought in the Father’s mind. This precludes the use of παρα (with) in that verse. Moreover we read in Hebrews 10:5 Wherefore when he cometh into the world, he saith, Sacrifice and offering thou wouldest not, but a body hast thou prepared me:
(No textual variants: http://openscriptures.org/prototypes/manuscript-comparator/?passage=heb+10%3A5&view=parallel&strongs=1)
He came into the world and considered a body (implying he had his own mind) prepared for him. This implies he pre-existed the incarnation as a distinct person. This interpretation is supplemented in John 6:41 The Jews then murmured at him, because he said, I am the bread which came down from heaven.
(No textual variants: http://openscriptures.org/prototypes/manuscript-comparator/?passage=john+6%3A41&view=parallel&strongs=1)
As the son glorified the Father on Earth, he now requests to have the glory he was given before the world was.
You are using the word had and given as predestination. Predestine is the greek προορίζω proorizō. Decree or pre-planned ordaining is προγράφω prographō. None of this appears in the passage. The Greek for had here is ἔχω echō. The word is in Imperfect tense, Active voice, Indicative mood.
http://www.blueletterbible.org/Bible.cfm?b=Jhn&c=17&v=1&t=KJV#conc/5
Imperfect tense denotes continual or repeated action, and the active voice denotes not a promise or a decree but a continual possession. The indicative mood indicates the same. Something that is pre-planned and decreed is not a continual possession but perfect in tense denoting something past once and for all and passive in voice.
http://www.blueletterbible.org/Bible.cfm?b=Jud&c=1&t=KJV&q=jude#conc/4
This would preclude this passage saying he would receive the glory later. Thus, Yahshua was possessing and active before the creation of the world. This clearly proves his pre-existence as a distinct person from the Father.
I would also add John 8:58, and 2 John 1:7