Preventing Burnout
You hit the gym every day, under the impression that doing more would yield better results, but instead, you end up always tired, with a plateauing progress and falling motivation. This is the result of overtraining. 
Overtraining is surprisingly common, especially among teenagers trying to push their limits without proper guidance. It happens when the amount of exercise you’re doing exceeds what your body can recover from. The worst part? Most teens don’t even realize they’re overtraining until the damage is already done. 
Spotting excessive training before it takes a toll on your health is crucial. A few ways to do that are by noticing a decline in performance, an increase in muscle soreness even on rest days, and a decrease in the motivation to go to the gym. If you start seeing some of these symptoms, then I recommend taking a few days off to recover before you go back, and then switching up your routine once you’re back.
To prevent burnout as a teen, I recommend going to the gym about 3-6 days a week, according to what your schedule permits and what your body seems to be comfortable with. Remember, progress in fitness doesn’t come from how much you train, but how well you recover from training. Overtraining might feel like dedication, but in the long run, it’s counterproductive. So that’s it; now go out there, train just the right amount, and crush it!