The ceremony of conferring the Aaronic Priesthood? This is nothing secret and happens to most LDS boys when they are 12 years old, usually during a Sunday meeting at a chapel, with their family members sitting in the room. A priesthood holder puts their hands on the boy's head and says something like "[Person's name], by the power of the Holy [Aaronic or Melchizedek] Priesthood that I hold, I lay my hands upon your head and confer upon you the Aaronic priesthood and ordain you to the office of deacon in The Church of Jesus Christ of Latter-day Saints, and this I do in the name of Jesus Christ, Amen." It's not a big secret and anyone who wants to sit in can.
Jesus said in John 8:58, "before Abraham was, I am." This was basically saying that he was Jehovah. But from our point of view it really doesn't matter that Jesus was talking in the Old Testament rather than His Father because Jesus only does the will of the Father. So whether it was Jesus speaking or the Father speaking in the Old Testament, they would have said the same thing. But still, if you're trinitarian and believe Jesus was his own father, I don't understand the objection here. It's like you're saying "that you believe Jesus was the God of the Old Testament proves you are not Christian," yet you also believe he is, as a member of the Trinity, God, and therefore the God of the Old Testament. Surely you're not saying that Jesus was not around before his mortal birth.
Sure, I believe the humanity of Jesus is distinct from his divinity in that he was born with a mortal body but was divine before, during, and after his mortal incarnation—and him being both the spiritual and physical Son of God was unique in all creation.
I realize that you've been taught that humanity cannot understand and make logical sense out of the doctrine of the trinity. We believe that it should make logical sense and therefore our version of the Godhead (Father, Son, and Holy Ghost) does make logical sense. We believe that they're three distinct individuals and they are one in purpose. That is a major difference between Mormons and the rest of Christianity. But in our point of view, just because we believe in a version of the Godhead that makes logical sense to us doesn't mean we don't believe Jesus is the Only Begotten Son of God who saved the world.
But if you didn't want to have this discussion, I'm not sure why you posted in this thread.