"Schools"?? I will assume you mean medical schools, but that overlooks the fact that the first hurdle you must clear is the policy toward AP credit at your undergrad institution. Most medical schools don't have a problem with AP credit as long as your undergrad transcript clearly shows the AP credit and the college class(number and description) for which they are giving you credit. Your "friend" also seems not to appreciate the competitive nature of medical school admission. Taking the most challenging classes offered at her high school is step toward a successful college experience. She should get that experience now, while it doesn't affect her pre-med GPA.
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Work smarter not harder! But its a good point.