I one of those that goes by the old adage 'sharp is sharp". I don't think shaving with a larger razor will give you a closer shave. Many prefer the larger razors as they have more weight to them they seem to just zip through the beard very easily but on the other hand a smaller blade is more manueverable and has more feedback. So its more a matter of what you prefer. With a smaller blade you naturally compensate with the required pressure as you shave.

A blade holding its sharpness has nothing to do with its size its a function of the quality of its materials and manufacture and of course your beard type. In my opinion if you have to restrop with a small blade you'll have to do it with a larger one of equal quality.

If I were you I would give it some more time and see what happens. If things don't improve with more experience then you might try a larger blade and see if it makes a difference for you.