I can completely understand where you are coming from. I chose this pattern for my first quilt and my mom didn't bother to tell me how hard it was. It taught me many valuable lessons..LOL
Sorry I can't be of much help as the whole thing was hard for me. But, I can tell you that the pattern I used the triangles were not semetrical. I made so many mistakes before I realized they had to be set a certain way to fit right. You might want to double check that.
I ended up being very happy that I chose this block because after doing something so hard, everything else felt easy and really fun without frustration. Now I'm not as afraid as I used to be of trying new things. Nothing has been as hard as that first quilt.
I wish you the best of luck:)
Lynette