@ucbalumnus thanks for the input. I ended having a more in depth conversation with @WayOutWestMom on PM, and she raised some of the same points. In the end, D and I decided that she should forgo the college credit. That’s why I ask the questions here. I thought I had a good idea, but 2 more experienced posters shot me down. Which is a good thing.
It probably wasn’t worth the risk that she would get stuck in a couple of advanced chem classes (that required real physics and extra semesters of calculus) with a bunch of chem and chem engineering majors. She is decent at chemistry (sitting on an A+ currently in the class after the first 2 prelims), but doesn’t love it and for that reason probably wouldn’t do great by comparison in a class with kids who are all chem majors at a selective college and who already made it through the weed out classes. Plus I do not think that the teacher in her class is all that great (D has had her before), so if everyone else has 2 semesters of real college general chem, they are going to be better prepared for the upper level classes than she would be.
I know that even in the 90’s medical school was competitive, but I never was interested in being a doctor so I have no idea how it compares to current admissions. Both of the eventual docs I took chem with had the same scholarship I did which required a 3.5 GPA, and I know they kept their scholarships. I’m pretty sure with some cushion. I’m guessing their overall GPA and science GPA’s were both pretty high by the end of college. The problem was just that first semester of general chem. We had the misfortune of a prof who made it clear that he thought teaching an intro class was beneath him, and he graded it accordingly, probably so the department head wouldn’t make him teach it again. IIRC over 60% of the class got either a D or an F. We all felt lucky to escape with a C.