I am as good as ready for first solo and the only reason I have not yet done it is because of a bit of a lack of confidence on my part.
This makes it sound as though going solo is up to you; it is not. Your instructor will decide when he considers you are ready, and simply get out and send you off.
The circuits that you fly leading up to solo are repetitious so that you cover all of the things necessary and don't leave anything out. You are not expected to be 100% or anywhere near it however the instructor wants to see you fly 3 safe circuits so that when he gets out, there is a high probability that you will repeat what you have already done.
Relax, enjoy what you are doing. When downwind, apply carb heat first, do the rest of the check and then make carb heat your last check, CH Cold!