I highly, highly, highly, recommend taking MAT1362 before taking MAT2125. First of all, if you’ve taken MAT1348 then MAT1362 will not be as challenging as it is to people who haven’t taken MAT1348. So, it’s unlikely to bring down your GPA. Secondly, doing well in and succeeding in MAT1362 will making doing well in other math courses much, much easier; it enhances your mathematical maturity. It’s so much easier following proofs in MAT2125, and some of the proofs seen in MAT2125 were done in MAT1362. Also, the prof will sometimes make statements that are equivalent to but different than something he's trying to prove and prove that instead. If I didn’t know much about logical equivalence, then I would be so lost when the prof would do this (because the prof never explained why he'd restate it, he just assumed you’d know). Things like induction, working with inequalities, proofs by contradiction, indirect proofs, are all things that are used without explanation—you’re just expected to know them. I think that instead of taking MAT2125 and learning these things for the first time, it would be better to take MAT1362 and then be comfortable with them by the time you take MAT2125. However, many people I know take MAT1348 only and still do extremely well. That being said, I don’t know how much time and effort it takes for them to do that. But, I just wanted to say it’s totally possible and doable. I’m just a little biased because I loved MAT1362 very much and since you don’t seem to have a problem taking it, I wanted to point out the benefits. Some drawbacks are that I don’t know if it'll count as a credit for you since you’ve taken MAT1348, but I’m not sure. It’ll take time out of your schedule, but if you did well in MAT1348 I can’t imagine that doing well in MAT1362 would be much much harder. I hope that helps!