I understand your concern, but money is not what will get you off-track, lack of focus will. You will find many distractions throughout your life which can cause you to fall behind in your grades or even drop out of school, but the only thing that will prevent it from happening is a strong will to keep your eye on the ball.
Starting to make money online has many positives, for example, you will gain a lot of knowledge and skills that will surely be useful no matter what you end up doing, you will also learn valuable business principles, and if you are successful you will have money to help you with school or ultimately build or scale up any initiative.
Having such an experience at an early age can only be beneficial, just stay focused and you will be fine, don't limit your possibilities out of fear, we can always control our destiny!