1. Understand that most of your height will be determined by genetics of your family.
Height is a polygenic trait, meaning that it's influenced by several
different genes. Having two short parents doesn't necessarily mean
you'll be short, just as two tall parents won't make you a towering
giant. However, if most of the people on both sides of your family are
short, odds are that you'll be short, too. Don't be discouraged, though.
The truth is that you can't know how tall you'll be until you reach
full physical adulthood in your mid twenties.
Calculate your projected height. Working in inches or centimeters,
you can try to predict your height based on the height of your parents.
Add up your mom and dad's heights (in inches or cm).
Add 5 inches (13 cm) if you're a boy; subtract 5 inches (13 cm) if you're a girl.
Divide by 2.
The answer is your predicted height, give or take 4 inches (10 cm).
Note that this isn't an absolute calculation, but it should be pretty
close.