Difficulty of Accelerated Spring/Summer Half-Term Classes

I’ve just completed my freshman year of college and am transferring to UM for the Spring half-term. I’ve been thinking to take Calc 3 and/or Econ 401, but I’m not sure if it’s a good idea.

Considering the rigor of UM, one of the reasons I applied to the half-term was to adjust to the campus-life with managing UM classes before taking a full 4+ course schedule. I’m worried, however, that taking more than one UM class for the first time at an accelerated pace might be too much, especially for classes such as these. I’ve heard Econ 401 is known to be one of the hardest classes at UM, especially for the prof who will teach it during the Spring (albeit he will be the same prof for the Fall anyway).

As an Econ major and aspiring Pub Pol dual-degree, both of these classes are prerequisites and requirements for future courses, so I’ll have more options for other classes or possibly even considering a BBA/minor if these classes are completed earlier. I do value actually learning the material in these classes, so, regardless of the grade I’d possibly receive, it might not be best to rush through this material in consideration to the learning process.

Has anybody had experience in taking courses in the Spring or Summer, and can speak to how much harder classes are at the accelerated pace, even if taking fewer classes? Has anybody taken either of these classes that can speak to whether an accelerated pace would be feasible to succeed with, especially Econ 401?