I am an undergraduate student and I am currently trying to decide whether to take undergraduate or graduate Quantum Mechanics. I plan to do a PhD in physics later on, so I assume that I will eventually take a graduate course in Quantum Mechanics, so I figure I might as well take it now, being that there are only math and physics prerequisites for which I have completed. The only trouble is whether I will be able to handle the course at the same level as the undergraduate course because I most certainly will not. So another question I had was whether when applying to graduate school, in general a lower grade in a graduate course is looked at as better than a higher grade in an undergraduate QM course. I'd just like some general advice on what would be better for learning (greater challenge more learning?) and what would be better for a future career and graduate school prospects.