Even if we dismiss Jesus being a ******* child, he still committed a sin by acting out in anger in the Temple. His actions there would have constituted a sin. Plus, the Bible tells us that he was human, and thus, sinful. More so, if we believe in the idea of the original sin, he was still born into sin then.
As for being an agnostic theist, here is a link that explains it very well:
Agnostic theism - Wikipedia, the free encyclopedia and more specifically for me:
Fideism - Wikipedia, the free encyclopedia