If you exercise too early and do those weight-bearing exercises, it will affect the development of bones, lead to short stature or abnormal figure, and affect the appearance. Generally speaking, children can do more flexible exercises to ensure their flexibility, such as pulling ligaments, or running and swimming properly, but don't overdo it, otherwise it will also affect their development. Real weight-bearing equipment exercise should wait until the body is fully developed. If you want to build beautiful muscles, the best time is in the years when you gradually gain weight. At this time, you will feel very efficient. No matter how others practice, you can easily practice your muscles bigger and bigger. Although fat is different from muscle, muscle is also transformed from fat. If there is no fat, it will only lead you to practice more and more, but you have too much fat, so it is not easy to build obvious muscles. So the best time is in the years when you gain weight. When you gain fat quickly, you have unconsciously turned it into muscle. By the way, if you think you have too much fat and don't want to become a big man, you can do some aerobic exercise first, such as long-distance running, swimming and cycling, so that you won't become a big man. I'm a fitness instructor, believe me, hehe.