In middle and high school, the brain is changing so much. Common sense and good judgment catch hold maybe by the mid-twenties. "Full" emotional maturity takes a few years longer. Beyond this biological timeline, teenagers are dealing with screen overload and massive, rapid changes in global social and environmental conditions.
How are you supposed to contain all this in your head? Don't try. Use your head to learn how to self-regulate by sorting the input and allowing it to move. Executive functioning is about helping bring some order to chaos, by planning, checking in, and directing the traffic in your brain, including your emotions. In other words, it's a set of processes that can transform stress into knowledge, motivation, and action.
If you investigate your process, you can develop tools to deal with stress (and school work) as it comes up. By understanding how stress arises and moves, you can use your attention to consciously work with it in constructive ways, adapting instead of collapsing.
Most importantly, you can learn to tell the difference between what you can handle by yourself and what you need help with. As this becomes clearer with practice, you gain confidence. No one can do it all alone. Knowing when you need help is power.
When you forget you're working until you realize you're done.