<p>I have heard that the very top theoretical math programs (like, the top ~10) are sticklers about grades. So if that is what you want, you may have trouble. However, coming out of a school of Duke’s reputation, I suspect that if you have research experience, good recommendations, and a good SOP (and don’t bomb the GRE), you can get in somewhere solid. And if you’re going to screw up, your freshman year is the time to do it, from the perspective of how it looks to grad programs. :p</p>
<p>
</p>
<p>Keep in mind that different schools are different (also, that tautologies are tautological; nevertheless, a surprising number of people seem to miss this particular tautology). The OP is coming out of a top-10 university that is at least, I would say, a top-25 math program. His/her classmates are likely to be an unusually talented bunch. Some of my MIT friends who were nowhere <em>near</em> the top 5-10% of their classes went on to be successful PhD students at good programs in their fields.</p>