This will not affect the height. Dumbbells mainly exercise the chest, shoulders and upper limbs, of which the chest is lying down, the upper limbs are generally sitting, the shoulders are generally sitting and exercising, and some movements are standing, so it will not affect the height development, and your age is very good. The exercise plan at this age is reasonable, and if the diet can keep up, the effect will be good. Dispel your worries and go for exercise!