i'm currently in math, and because of overloading, i only need 7 more math classes to finish my degree (i'm going into 3rd year)
this is why i've thought about pursuing a minor in comp sci, i've already taken a few classes and i have an aptitude for it. however, after looking up more 3rd and 4th year classes, i've found some more math that i'd want to take, but i'm not sure which would be more useful.
in addition, if i take the minor in comp sci, then i'd have almost no fourth year math classes, which might look bad if i decide to go into grad school

Depends what math you are interested in. The mainstream ones are analysis, algebra, topology and their subfields. I would say more math is better because you can easily switch into comp sci if you want to go comp sci for graduate school.

My co-op coordinator keeps telling me that programming is an asset and I should really take more comp sci classes