My daughter was also in this situation. However, she took Calc I VERY seriously, used Khan academy, her books, her computer, her study time to help another athlete who missed class on Wednesdays (and teaching him helped her a lot). Many of those re-taking calc I thought they knew it all and didn’t need to study.
Daughter got an A. Many of the others didn’t.
Glad your D had a better experience. My S also took the class 'VERY seriously" and utilized every resource available to him (I hope you were not meaning to imply otherwise) and he did fine in the end. My point was that not having calculus in HS made the class more challenging and time consuming than it would have been had he taken calculus in HS.
Wasn’t saying anything about your son at all and was agreeing with you that those who hadn’t had calc in hs have to work really hard in Calc I in college. I said that many (way more than half of daughter’s class at an engineering college) were taking Calc I as a repeat after having it in hs and they didn’t take it seriously, thought they already knew the material so didn’t need to study. My daughter was petrified going into college (engineering) that she wasn’t good enough as she hadn’t had calc or AP chem. She worked every night on calc while others played games on their phones in class because they were just refreshing their knowledge. She used every resource available to her (Khan, TA help, math tutoring, putting her butt in the chair in the library study tables every night) as did your son.
My nephew did not have calc in hs either although he went to a very challenging hs. He had to repeat Calc I, although I think that had a lot to do with beer and failing to do the work. According to my sister, it was because his school was harder than my daughter’s; they had the same textbook.
OP’s daughter doesn’t HAVE to have calc in hs, but it usually makes life easier. I don’t think it will prevent her from getting into a top college, which was the original question.