I agree with the self-confidence theme.
Confidence is best, when it is genuine. In other words, learn. Knowledge is power.
Exercise, and develop your mind/body. Then, you can have true confidence. Once you obtain a higher level of understanding of your world, you will become more confident. Fear, is based on the unknown. The more you understand about your world, the less will be unknown/scary.
Knowledge will give you the ability to gain experience. Experience, coupled with knowledge, is a formidable force, and makes a formidable person. Then, it is important to humble yourself, and shape your knowledge/power into who you want to be. Your knowledge will give you the power to spread your knowledge to others, making you an even more powerful being!
At 13, you’ve got your destiny in your hands. There is no limit, to what you wish to achieve. You just have to find your path, and go.
Best of luck!
Peace n Love.