The more advanced chemistry courses may have more difficult material, or require additional prerequisites. Not an issue if she will be a chemistry, chemical engineering, or other major who will take those courses anyway, but may be an issue if she would not otherwise take them.
Advanced inorganic chemistry may require only general chemistry as a prerequisite, but physical chemistry may also require physics (sometimes calculus-based physics) as a prerequisite and/or math beyond single variable calculus.
So if she does want to use credit from the local college general chemistry (or AP credit) to take advanced placement, she should check the old final exams of her eventual college’s general chemistry courses to be sure that she knows the material well based on that college’s expectations, since she may need it in organic chemistry, advanced inorganic chemistry, etc…
One other issue is that if she does take college or AP credit for general chemistry, but her eventual college does not accept it for advanced placement, then she would have to repeat general chemistry and have to mark “repeat” on the medical school application.
But was medical school admission less competitive back then?