I was Approached by a Mormon and so I asked Him This...

I am learning about Mormonism. I was approached by a Mormon who told me God always existed and that they always existed too.

I thought to myself if people always existed why can't we remember having always existed? Is it not true God "who alone" (1 Tim. 6.16) was "from everlasting" (Neh. 9.5)?

"Ye are my witnesses, saith Jehovah, and my servant whom I have chosen; that ye may know and believe me, and understand that I am he: before me there was no God formed, neither shall there be after me" (Isaiah 43.10). So I read this as saying nothing existed before time and space but God alone.

"For there is one God; and there is none other but he" (Mark 12.32). There is nothing else beside God before time and space.

Satan rebelled and said, "I will ascend above the heights of the clouds; I will be like the most High" (Is. 14.14), claiming he existed for an eternity in the past.

"I am the first and I am the last; and beside me there is no God" (Is. 44.6). If God was first then there is nothing that always existed with God before time and space.

"In the beginning God created the heaven and the earth" (Gen. 1.1). So there was nothing but God then God created.

"All things were made by him [Jesus]; and without him was not any thing made that was made" (John 1.3). But Mormons/LDS say Jesus didn't create everything. Who is right?