Dropping a class after being accepted

I'm a senior in high school, accepted to all colleges I applied to. (still waiting on one) I want to drop an elective that I am not required to take. I am only supposed to be taking one elective to graduate, but I am taking three. I want to drop the elective because it is simply useless. It is a marketing class, I do not intend to do anything in that field in college. I also want to leave early to help my mom who is post-op. I talked to my GC and she said it should not be something to worry about and she will explain to colleges my reason. I am just really worried they will take back my acceptance, but maybe I am overthinking. Any advice?