Do not stress! I pushed my exam last year (had to pay as well) and the extra time was exactly what I needed. Felt iffy about it at the time, but it all worked out (attending a T-5 school). Good luck!!
I did 75% of the CC (so everything except RC) before I took my second prep test because I was really curious what kind of progress I was making. My diagnostic was a 156 and I went up 13 points to a 169 just from 3/4 of the CC. Then once I had done 8…