Correct, though you dont seem to understand why.
Two reasons which you are struggling with:
1. Revelation 1:5 first born from the dead to immortality (no others in human history!)
Nothing in Revelation 1:5 KJV about that "to immortality" - just "first born from the dead", which is a monkey wrench in your machinery, seeing many others resurrected before Jesus.
2. John 3:13 No one in Heaven from this creation except the Lord Jesus Christ (explicit!) Return when you have dealt with these.
Context, my friend! What's the context of Jesus' conversation with Nicodemus?
Understanding and teaching heavenly things - which learned teacher Nicodemus could not teach, notwithstanding lesser men.
Jesus is saying, "And no man ascendeth up to heaven
(to learn of heavenly things and come down to teach them) save the Son of Man which is in heaven". How do we know? Because the OT plainly tells us God carried Elijah to heaven! Not to an unmarked grave, not to the 1st heaven where the birds fly, nor the 2nd heaven where the stars twinkle, but to the 3rd heaven where is the glory of God. It is this glory with which Moses and Elijah "appeared in glory" to Jesus.
Please stop denying the fact that God took Elijah to heaven and inserting human ideas about Elijah being killed and buried by God, friend.