The question is this...
how tall will i be
I don't know where I originally heard this, but have always thought you double your height at age two to determine your ultimate height. I was able to confirm this at InteliHealth:
Can Height Be Predicted?
Genes, nutrition, and overall health have their effects right from the beginning. Rather predictably, we achieve about half of our adult height by age 2 — so, one way to predict ultimate height is simply to double the height achieved by the second birthday. Other ways to predict height take information from childhood growth charts (see below), your parents’ height, and a reading of your "bone age." Bone age is assessed by X-rays that indicate how much development has already occurred in the skeleton and how much more is possible; for example, if the growth plates are still open, more growth is likely. The closer you are to final height (by virtue of your age or the finding of closed growth plates on X-rays), the better these formulas predict height.
Additional resources on this...
Parents' Heights Don't Always Predict Child's Height - Reuters Health
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