Don't overthink it trying to decode some literal or deep meaning, because people get obsessed with that and then it just creates more anxiety. Dreams like this are actually pretty straightforward: your brain is recycling a stress template it learned decades ago. School was a place where you experienced real pressure, exams, evaluation, that feeling of not being prepared. That got hardwired as a "typical fear scenario," and when you're now dealing with stressful situations at work (an important presentation, a performance review, a project you're not on top of), your subconscious pulls out that old tape from school because it's still the best example it has of "this could go wrong."
What's interesting is that these dreams probably show up more when you're going through real periods of stress at work or in your personal life, even if you're not consciously aware of it. Your brain isn't saying "oh, you need to go back to studying," it's using that familiar image of distress to process your current anxiety. It's like it's saying "remember that terrible feeling of being out of control you had back then, well something similar is happening now."
Most people have recurring dreams like this their whole lives - some about school, others about being chased or falling. If you wake up upset but then the day goes on normally, there's nothing wrong with you. But if you're left with a sense of unease that affects you the next day, or you're having these dreams every night, then it's worth stopping to think about what's actually stressing you out right now and whether there's something you can do about it. But the dream itself isn't a coded message, it's just your mind being a bit lazy and reusing old material.