Congratulations on having made a truly beautiful quilt!
That said, I agree with your advice to other newbies to start with a smaller project.
FWW. I've pieced a whole bunch of log cabin blocks similar to yours with white squares in their centers - which I intend to machine-embroider. I still haven't gotten up the courage, though. (If I screw up, everything is ruined, right ;-)) Your post has given me some much needed encouragement.
Next time, I'll do the machine embroidery BEFORE I cut those inner squares.