Yes, it is important. It is something colleges look at and also part time jobs may be interested in your GPA. Having good grades will also prepare you for college.
Yes! Most people who have good grades work hard for them. A high GPA indicates to future employers that you are a responsible, productive worker who is worth hiring.
Having a good GPA average in high school is very important. It is especially important for those students that wish to get into a good college. Scholarships are usually given out based on the high gpas of students.