If you are worried about your height, talk to your parents and your doctor. Most kids don't have a growth problem that needs help from a doctor, but it's always OK to ask if you're concerned.
So for most kids, it seems like there's not much to do but wait to see how it all turns out. But you can do something right now: Eat healthy and take care of yourself. If you get the nutrition, sleep, and exercise you need, you're likely to reach your maximum potential height. In other words, you'll grow as tall as you were meant to grow.
And even though you may hear people say it, taking extra vitamins or supplements that you can buy in a store won't help you get taller. Just stick to a healthy diet if you want to be the tallest you can be!