The Bible talks about a first couple, I agree. I don’t see anywhere that it talks about a “literal” first couple, though.
Luk 3:37-38 the son of Methuselah, the son of Enoch, the son of Jared, the son of Mahalaleel, the son of Cainan, the son of Enos, the son of Seth, the son of Adam, the son of God.
1Ti 2:13 For Adam was formed first, then Eve;