I think the words must all be correct in the Bible, therefore, If Jesus had something then, He must have been there then to have it. Yes, He's putting the emphasis on glory, but He defines that glory as the glory He had before.
Much love!
The question is whether someone can "have" something before they are born or even exist. (I'm not arguing against the Trinity doctrine. The point is centered strictly on the meaning of the verse in question.) Can we find an example of this in everyday life? Can we find an example of someone "having" something before they were born, for instance?
Consider the principle of inheritance. Upon the age of maturity, would it make sense for a firstborn son to say to his father, "Father, please give me the inheritance I had
with you before I was born?" Granted, it might sound funny, but it isn't absurd. Possession, in this instance, isn't predicated on ownership. The basis of the declaration is a promise. In this instance, the firstborn "has" the inheritance, even before he is born, because the inheritance is "with" the father, kept in the father's possession until the age of maturity.
In other words, I believe Jesus understood that glory was his inheritance, and that the father kept it for him to be given at the appropriate time. Jesus had it "with" the Father, even before the world was created.
You might say, "but no, Jesus is saying that he existed with the Father and they both had glory together." In other words, "Restore the glory to me that we previously shared together." The words can certainly be understood that way. Nevertheless, in this context, Jesus has focused on a particular instance of glory rather than the general state of glory. The particular instance of glorification Jesus has in mind is the cross.
The glory Jesus was to inherit, was the glory he would receive after his resurrection.
Notice . . . John 17:1
Jesus spoke these things; and lifting up His eyes to heaven, He said, “Father, the hour has come; glorify Your Son, that the Son may glorify You . . .
Jesus would allow himself to be arrested, tortured and killed at the hands of the state. He knew he would die and be buried for three days. He also knew that the Father would raise him after three days. Thus, on the day of his resurrection, while the father glorified his son, he glorified himself also. Through that one act, both father and son were glorified together.