We most certainly do learn from Jesus that he always was:
Joh 8:24 I told you that you would die in your sins, for unless you believe that I am he you will die in your sins." (ESV)
Joh 8:28 So Jesus said to them, "When you have lifted up the Son of Man, then you will know that I am he, and that I do nothing on my own authority, but speak just as the Father taught me. (ESV)
Note that "he" is not in the Greek text; it has been added by translators.
Joh 8:58 Jesus said to them, "Truly, truly, I say to you, before Abraham was, I am." (ESV)
Three instances of Jesus claiming to be the I AM, in one chapter. He cannot be the I AM and have not existed at some point in the past. Being the I AM means that he has always existed.
Why do you insist on believing something to be true that is self-contradictory? That is irrational.
That Jesus never dies is utterly irrelevant to his being God. At one point in the future believers will be changed, never to die, but that clearly won't make us God. God doesn't die because he is eternal, having always existed. And that is what we learn about Jesus, as I've shown above.
Then, if Jesus truly "is all that the Father is"--something I agree with--then it follows that he must also be eternal, having always existed. To then say "no," is to contradict everything.
Can a woman be pregnant and not pregnant at the same time?