Grad class as an undergrad, not going so well

[prospectivecsgrad]

So, I am currently taking a grad class as an undergrad, which is in one of my areas of interest, but it is also known to be very difficult.  I have no idea where I stand in the class aside from the first assignment, which I didn't too well on (at least compared to the average), and the next two homeworks I haven't been feeling too confident either.  I plan to discuss with the professor, but I am worried I may get a B-, if not lower, based on the distribution from past semesters that this class was offered.  What implications may this have on me getting into (hopefully) grad school?