Are you already in Track and Field? The students who I worked with who were in Track and Field spent hours, year-round, in training. To stay on their teams, their GPA had to stay strong. Your studies come first.
If you spend your time on EC’s without rest, study time, and enjoyment, you’ll burn-out fast. All of your activities will take some investment in time. As you go through sophomore, junior and senior years, your study hours will need to increase.
Study well, first and foremost. Enjoy high school. Do what’s important for you. Mom will be proud regardless of any perfect grades.