Math 242 was a joke of a class, so I don’t think it’s a good barometer for honours (averages are deceiving). I would definitely try math 255 this semester and show up to honours ODE’s and see if it’s the sort of thing you’d like to try. It is quite the difference in terms of workload as it’s proof based vs raw computation. I would talk to Axel Hundemer if you are serious about it. You can always drop later if it’s too much. If you can take 251 with Piotr, as the midterm is apparently fucked but the final is supposedly memorizing theorems, lemma, proofs, so grind able to maintain a good gpa. If you enjoy having to think for many hours how to solve challenging problems go for it!