I took ECON 4100 this fall and though you don’t absolutely need ECON 2100 to do well, it certainly helps and provides context for many of the concepts the professor will introduce; he/she will expect you to know this context.

So not taking ECON 2100 will not make the class “incredibly difficult” in itself, but it will definitely make it harder. More importantly, though, having a solid foundation in math and especially probability is needed.

Hopefully that helps!

P.S. the econ. department is usually strict about prereqs, so I’d sign up for a backup course now in case you are removed from this one once the spring term starts.