New King James Version (NKJV)
56 Your father Abraham rejoiced to see My day, and he saw it and was glad.
57 Then the Jews said to Him, You are not yet fifty years old, and have You seen Abraham?
58 Jesus said to them, Most assuredly, I say to you, before Abraham was, I AM.
Why did you capitalize I AM instead of how it was written as I am ?
The Greek root does say 'am' in the present tense at John 8 v 58.
But, the expression of past time appears in the sentence, so the present-tense verb can be translated as if it had begun in the past time continuing up the the present time which can translate as 'I have been'.
So, before Abraham was then Jesus existed. Existed in the heavens as the beginning of the creation by God. [Rev. 1v5 A; 3 v14 B]