You make good points. May i introduce you to Islam?
https://en.wikipedia.org/wiki/Muhammad
https://en.wikipedia.org/wiki/Muhammad_in_Islam
https://en.wikipedia.org/wiki/Quran
The final prophet Mohammed s.a.s. whose life and effect are well documented as well as the direct word of Allah s.w.t., preserved as original in the Arabic language of revelation in the Quran. You should not though that according to Islam Jesus was merely a human messenger as Allah neither was born nor gives birth. In the same wake Allah is one and not three. But these concepts were added by the church to the Christian theology four hundred years after the life of Jesus.
https://en.wikipedia.org/wiki/First_Council_of_Nicaea
Jesus as literal son of god was only established some 400 years later. And when later the records of the gospel got translated through multiple languages it seems very plausible to me, that under the assumption that Jesus should be the literal son of god, this sentence is supposed to be worded to confirm that. It is as easy as forgetting a half sentence like "HE said" or turn a third person into a first person form. Or to loose the context that he was announced already before Ibrahim etc.