Throughout High School I have received all A’s in the most difficult STEM courseload however I have always taken College-Prep English rather than honors/AP. In 12th grade, I decided to take AP Literature to continue showing rigor. If I end with a B first semester, how negatively will this reflect on my regular decision application?
Where are you applying and for what area of study? If you are saying you will have one B one semester your entire HS career, I don’t think it will move the needle too much.
For colleges that require mid-year reports showing first semester grades, reporting one B out of all A’s is unlikely to have any negative impact. For the large number of colleges that actually do not require mid-year reports and make admission decisions based on grades through junior year, those will not even know of the grade until you submit your final transcript after completing senior year, and having one B is almost certainly not going to result in a withdrawal of any admission already given.
I think you can leave out the “almost”.