I hope you put it away for a couple of days. I noticed, yes, the pink border on the left is smaller at the top, yes, there is more space between the top two black blocks, yes, the lower left triangle is smaller.
So, I would take off all the sides, SQUARE up the center block. Sew a little deeper seam in the top row between the two black blocks, then sew the pinwheels on. If you already trimmed the pink border, you will need to make sure they are all the same size before putting them back on. I hope this helps. (I like to do my best, even if it is for charity.)