What Would be the best choice?

I’m a rising senior in highschool and over the summer I took Calculus II at my local community college. I was planning to finish Calculus (III and IV) during my senior year but I asked my counselor whether I could do that or not and she said I needed to attend at least 5 classes at my school which makes it impossiblee for me to commute to my local CC to take the classes. I was wondering whether I should take Calculus BC even though I took Calculus II over the summer because I’m afraid I may forget Calculus which is essential to my major I’m trying to do (Civil Engineering). I may try to push the issue to my principle, but if I’m unable to take it at CC would my best choice be to take Calculus BC just to keep it fresh in my head?

No. It’s a waste of a class period to duplicate material.

I’m going to possibly disagree with @skieurope. If Cal BC is really the only math class you can take and get credit for at your high school I would take it. Colleges used to say 3-4 years of math and more are saying 4 years of math and some like UMass Amherst say Mathematics (Algebra II minimum): 4 including math in the senior year of high school. I would talk to gc and ask about it since you might
not get credit.

I’ll expand on my earlier thoughts although my advice remains unchanged. But since the OP has not provided the HS course catalog or the student handbook, we’re kinda guessing here.

Ideally, the OP can work something out with the HS so that s/he can continue with calc III at the CC. But failing that, if there are other math courses to take at the HS, e.g. AP Stats, I would opt for that. Alternatively, s/he could possibly do an independent study with online resources for advanced math if HS policy permits. If college credit is a concern, s/he can still take the AP exam. But taking Calc BC (assuming a strong performance in Calc II at the CC) is a waste. Regardless of the final outcome, the GC can (and should) use the rec to explain the school policy that stifles a student’s ability to challenge him/herself.

Water under the bridge, but this is really something that should have been planned for in advance, so different decisions could have been made to maximize summer productivity, whether with another course option or something non-academic. But what’s done is done.