One of the definitions of agnosticism is that this person believes that the existence of God is in principle unprovable - either positively or negatively.
Well, I do not believe you can prove the existence of God empirically, and your statement would therefore make me an agnostic. But I am not an agnostic.
Somewhere in your statement there seems to be a flaw, and that flaw resides in the bolded part.
I think it should be modified to this:
....in principle unknowable....
This is different from unprovable.
BTS