So if your sister were to give birth and you were not right in the same room she was giving birth in does that mean you were not there to give witness that your sister actually did have a baby?

That's not the point. Why you interject in a conversation I'm having with Standing Up when you're missing the point is beyond me.
No one is disputing that a baby would have been born, because I'd be able to see it, just as say, the Apostle John would have been able to see Jesus.
However the details of the birth were not witnessed by me therefore I would need to have that information passed on to me. If you're a
sola scriptura buff, then to continue the analogy my sister would have written down an account and passed it on to me rather than just tell me.
Had you actually read what I wrote you'd have noted that I said that Mary must have passed the details of Jesus' birth on to the writers of the Gospels. I'm not disputing that John, for instance was a 'witness' to
some aspects of Jesus' life. I was not arguing against someone not being there, but was refuting StandingUp's claim about them being a witness.
StandingUp said that they had to be witnesses to be chosen. If you'd read this you might well have regarded further what you were going to say in interjecting in our conversation.
IF as you now put it that one only need be a witness to the 'result' of an event - as your put in your analogy of me and my sister* then ANYONE who saw people preaching that Christ has risen could be called a 'witness'.
Is this the point you wish to make?
Also, when you can find some evidence for
sola scriptura from the Bible itself, that would be really handy - as it's part of the OP
If you'd like to address how the books of the bible chose themselves that would be great too.
*-by the way she never had children and she's passed on.