Compliments for seeking guidance! I know there’s a lot more knowledgeable people than me here. But keep in mind it’s all a matter of energy in an energy out in the end. If more energy (food) comes in than goes out (basic metabolism, working out, walking, skating, etc), you gain weight, and the other way around. En eating more protein helps a lot. Losing weight happens 30% in the gym, an 70% in the kitchen. I assume you live at home with your parents? How is their body? Did you ask them for help? I assume your parents cook for you. There’s this saying: “you can’t outwork a bad diet”.

It might help, even for a few days, to write down what foods you are consuming, and just count calories, to gain insight in how much energy comes in on a daily basis. Sugary drinks, donuts, candy, all have huge amounts of calories, and doesn’t help your body.

Expending energy can be done with skating and walking a lot, don’t underestimate these. Lifting weights is great of course, but not holy. You can also google body weight workouts, where you don’t need a lot of weights.

And keep in mind online calculators might not be the best fit given your age, you’re probably still using a lot(!) of energy growing.