Arbor KAL

I started my first knit-a-long doing a shirt, which is my first shirt. This has not gotten off to a very good start so far. First of all, I ordered my yarn late so it didn't show up until almost a week after the KAL started, secondly another woman in my group is a turbo knitter, so keeping up is going to be a struggle as it is, but perhaps that will work out well for me as she will have completed the shirt long before I do and will be able to help me with EVERY issue I may encounter. Another issue I am having is with the sizing. I went by the size of my bust and just assumed it would work out all right, but now that I've officially frogged it for the first time I am concerned that this shirt is going to be HUGE! When I look at the provisional cast on that I did it can wrap around the largest part of me almost 2 whole times, what does this mean? Finally I was unable to keep my knitting from twisting, I don't normally freak out about this, however it's a big project and I don't want to frog it over and over and over again and I don't know how to keep it from twisting when there are tons of stitches on the needle. HELP!