Faking the vibe while you learn is normal. Faking the results is a countdown to getting caught.

Acting more settled than you feel is how most people survive a new room, and there is nothing wrong with it. Confidence is allowed to arrive late. What breaks is claiming outcomes you did not produce, because those get checked and the check always comes at the worst possible moment.

Notice which one you are doing. A steady voice while you are still figuring it out is fine. Numbers, credits or skills you do not have are worth correcting now, quietly, while correcting is still cheap.