I think the problem is in the cutting. You need to make sure the fabric is pressed and folded carefully before you begin. Here's M'Liss Rae Hawley's tips for getting it right:
1.
Fold fabric from selvage to selvage (full width of fabric) or selvage to cut edge (fat quarter).
2.
Hold the fabric in the air and study the drape. Disregard the cut ends, instead, move the selvages from side to side til the fabric is perfectly flat.
3.
Stop. Set the fabric on the cutting mat and make the second fold: selvage to folded edge. If you have a large piece, try to break it down so you can work with a manageable amount.
4.
Place folded fabric on the mat, with the fold facing you. Position your ruler on the right-hand edge of the fabric, so it is perpendicular to the fold.
5.
Trim to square up....
6.
Rotate the mat or the fabric and repeat to trim the opposite edge.
I found these tips very useful when starting out. All is not lost with your wonky blocks, just a bit of a tedious task trimming them all individually before you get piecing.
Hope I explained it clearly......don't give up, it's very pretty fabric and show us how you progress....we love pictures.