I just recently got a long arm quilting machine and my first tries were so horrible!! I was trying to do more than my skill and it showed. I see all these videos where they just GO FOR IT and so FAST that I thought that I had to do that too. Heck no... at least not yet. I thought it would be "cheating" to mark my pattern. I also found that I was starting quilting without having a very clear idea of what I was going to do.
My advice is to start simply, plan it out, and mark your pattern.