Beside the fact that only one translation I found (NRS) translated it as the 'begotten' as the perfect (has been), every other translation translated it as is (NASb, NIV, KJV, Geneva,) how does that passage say that regeneration and faith occur at the same time?
John is simply saying if you believe then you have been born of God, not that you were born of God and believed at the same time!
We are saved by faith which precedes regeneration.
Maybe you will listen to the Bible!