I don't have much experience in styling design, but I often help people do non-mainstream or organize photos. I think you should pay attention to the hairstyle of your hair, that is, the hanging seams on both sides should not be too short in front of your ears, so that your face will look longer and your head will fly shorter. If we combine the two, it will improve a lot. Wear a V-neck instead of a round neck.
I hope I can help you. Keep an open mind. Now people are interested in your strength, not your appearance. Don't be embarrassed about it. Besides, you are only 13 years old now. People will change when they grow up. Don't worry about it, okay?