Every single time I see these threads I strongly disagree with people who say "just take the credit." This is because of personal experience, so please hear me out.
1) I started taking a foreign language at Tech and completed it through 3000 level. I realized I actually wasn't comfortable speaking at all, so I had to go back to the 1000-level texts and relearn all the basic vocab til I could do it in my sleep. I can now think and speak a language that traditionally is very hard for native speakers (not perfectly, but can make myself understood). If I had taken the time in undergrad to focus on listening to every basic sound, producing them, knowing basic vocab in my sleep, I would have been speaking years ago. Fundamentals are everything.
2) A year ago when I started working, I had to work on a project that involves a quantitative understanding of QM.. I'm an engineer who got A's in every physics and math course I took, but I did not know the material well enough to tackle the project with confidence. I went to a QM text, which I kind of got, then back to Feynman lectures (which are not quantitative), then found a basics physics textbook, which wasn't quantitative or fundamental enough, then to a fucking diff EQ book by Cauchy... which I had to work through, then work through two QM books (one for engineers and the monograph by Heisenberg, dry as a fucking desert) before I could really contribute as part of the team. And when you're older, understanding math just takes soooo much longer. Fundamentals are everything.
As for people telling you to self-study the material for calc 1 and 2 over summer.. for me, I can never self study something as dense as math unless I have a very real motivation to. I think you'll find it hard not to give up after a couple weeks of boring pain studying material that is familiar enough to be not interesting but unfamiliar enough that you still need to read it.
Just take the class. In any thread where someone asks your question and the answer is "Just take the free credit," there's not a single actual reason given why you should do that advice. "It's the consensus" and "the class is hard" are not valid reasons to not try and understand calculus.