Paralysed by the Pattern.

Have you ever been sewing quilt pieces together , when all of a sudden, you're unable to go further for fear of ruining the block?
I've been at this stage with a particular block for nearly 12 months.  I don't understand why, but I am.
I've been trying to finish a few quilts that don't need much, and have been sitting up one end of my sewing table, waiting.  Mostly little doll sized quilts.
However, I have a large quilt that I love, but I just can't seem to move on it.

I'm making "California Star" by  Michelle Yeo.  The four large circles are paper pieced in 3 circle sections using Michelle's freezer paper method.  Unlike normal paper foundation piecing, I quite like her method.  However, now I'm left with 3 circles and I'm terrified to sew them together in case I muck them up!

The centre is fairly easy! LOL.

However, these rings really worry me.
Wish me luck as I attempt to sew these together with much trepidation.