1. So why did you initially deny that your vision was from God?
When you said "received by God himself" I understood like a pizza boy.
2. How do you know that your vision is not convincing to anyone else?
It's convincing to me. Idk about others.
Have you told anyone else about the specific details/ specific content of your vision?
Yes.
You refused to provide the specific details/ specific content of your vision when someone from this forum asked you to share that information.
I just share this information irl.
3. What about your vision makes you certain that it was from God via an angel?
How were you able to tell that your vision was from God via an angel?
It's a personal axiom (I'd experienced a paranormal event). Just like I accept the several axioms in the scientific method (the entire physical world is understandable to human mind, for instance).