Most people reach max height in late teens w/o nutritional problems and chronic childhood illness height based mainly on genes..wat do yu mean by that?

Height growth: Most of the time your height velocity (how quickly you increase your height) is genetically determined. Boys usually finish growing in their late teens, but may have a second small growth spurt after 18 (if it runs in your family). Eat healthy foods and exercise regularly, but you really can't change your height.

It means: that your height is genetically determined and you will reach your genetically determined height if you are well nourished, have no chronic illness that can interfere with nutrition or energy metabolism, and are not under unusual physical or emotional stress.