Early puberty is related to diet. Eating a lot of out-of-season fruits and vegetables, most of which are destroyed by chemicals, will have a certain impact on the body, especially on children. For example, eating oranges in winter; Eat watermelon in summer. There is no harm in eating seasonal fruits.
The most direct influence of children's premature development is height. If it's too early, they'll end it too early.
The height will not change much. It is normal that boys should start to develop around 13 years old.