I'm going to tell a classmate to reconsider her career in medicine
Why tell her to reconsider her career?
She is just not suited for it.
It is not up to you to decide what she does with her career. Making comments like this is not helpful and can only put someone down.
I'm going to do it anyways.
You should not do this. Your classmate will end up resenting you for it and it does not help. She can choose her own career.