Answer 1

Hi Bradley, learning programming isn’t that easy for a high school student (i can relate to this when i was one...), and she will not be learning a lot of concepts in programming every day like what she is doing at school, let her learn a single concept every day for 5 minutes or 10 minutes and practice it immediately and learn 2 days in a row for C# then 2 days for Unity then back to C# and so on, in less then a year she will be very good at C# and Unity and she will be able to make great projects and games, and this will not affect her study a lot so she will be doing good at school.
hope I helped!.
NOTE: I am not a game developer so I am just giving you a way to learn C# while learning Unity without killing the high school GPA.
good luck❤