Most women stop growing at a certain age, but at the age of 21 or during pregnancies and essentially high hormonal times, they can experiencing another generally small growth spurt. With pregnancy, it is usually because the spine is more stretched out. But your height in general is determined by your bone length. Boys usually grow the most between 12 and 15 and girls between the ages of 10 and 13. But you can continue to grow more slowly up to the age of 21. From there, you may gradually shrink due to loss of bone density over time. The research in terms of height is unclear. Most people will stay around the height of their parents or somewhere in between. Boys actually have a higher chance of growing more at an older age. But there are some who say nutritional factors have a great prevalence in this. For example, those who are malnourished tend to be stunted in their growth among other things. In addition, if you don’t have enough meat and dairy in your diet, you are unlikely to grow to your full potential. So in those cases, I have actually seen some experience a sudden growth spurt when those particular nutrients were supplemented into their diets, even a few inches.