We are all frauds
If you don't feel like a fraud in what you are doing (or trying to do) at least a little every day, then you aren't pushing yourself enough.
Worse, you aren't learning enough.
Sure it's stressful worrying that you might be 'exposed' any minute and that you might not be able to pull if off this time.
But a healthy amount of stress helps you to focus and keeps you closer to peak performance levels.
Of course that doesn't mean you should be a total fraud.
Instead just use it as a tool to "fake it until you make it".
And each time you "make it" (because we both know you will), push the goal a bit further out.
Because the moment you stop pushing the goal out, it's time to get out of the game and go enjoy what the rest of life has to offer (and there are always a lot of great things still left to enjoy out there).