Does the noble verse: (O Prophet, when believing women come to you to pledge allegiance to you) refer to the First Pledge of Aqabah, knowing that there were no women present in it?

The correct view is that the First Pledge of Aqabah was based on hearing and obeying, enjoining good and forbidding evil, speaking the truth, and on loyalty and support for the Prophet, peace and blessings be upon him, protecting him as they would protect themselves, their wives, and their children. As for pledging allegiance to the likes of the pledge of women, which is mentioned in Surat Al-Mumtahanah, that occurred later, as confirmed by Al-Hafiz Ibn Hajar and other verifying scholars.