I have reviewed the theoretical trajectory of my research topic and I see gaps that I would like to fill with my own proposed theory. Is it too early in my career to put forward a theory? I am just a PhD student. If I can put forth a theory at this stage, what is the best way to go about it? Will the fact that I am a junior faculty member and a student affect the reception of my theory in the international scholarship community?
A theory (assuming you mean hypothesis or idea, not proven theorem) is the start of the process. You might come up with one at any time! Of course it will probably be wrong: this is nothing against you, its just that most interesting theories turn out to be wrong.
The interesting challenge, and most of the work, comes next, when you try to show that the theory is true or false, either empirically or analytically...
of course. that is the nature of a PhD. Of course, if it is anything contentious then you need to have arguments and evidence. And of course "extraordinary theories require extraordinary evidence". That said, coming up a hypothesis or two is evidence of critical thought. Be prepared to defend it. And do so with courtesy and good will.