It shouldn't affect her high school GPA:
"For students who entered Grade 6 during or after the 2016—2017 school year, the final grade and credit earned for high school courses successfully completed while in middle school will be reported on the high school transcript, but will not be calculated into the
cumulative GPA/WGPA, unless the grade earned improves the student’s cumulative GPA/WGPA. If the course grade for a high school course taken in middle school improves the student’s cumulative GPA/WGPA, it will be applied automatically by MCPS. Parents/guardians may opt out of the automatic calculation by contacting the school counselor."
https://ww2.montgomeryschoolsmd.org/departments/policy/pdf/ikcra.pdf