I left college 3 years ago. Do you think it’s a good idea to go back and pick up where I left off, i.e. Calculus 3. I have done no math in these three years and am unsure if I will be able to handle it.
You can refresh your memory with something like Khan Academy, and also use that to determine whether you’re prepared for Calculus 3. Taking a placement test again would also be a good idea.
I would certainly retake Calc 2. Most likely you’ll have some vague recollection of the concepts, but it’ll be useful to refresh.