To answer this question - it's probably a good idea to understand the following:

1. How did we get tall?

https://www.theatlantic.com/health/archive/2014/05/how-we-get-tall/361881/

https://www.smithsonianmag.com/smart-news/heres-why-dutch-are-so-tall-180954930/

https://www.sciencemag.org/news/2015/04/did-natural-selection-make-dutch-tallest-people-planet

http://rspb.royalsocietypublishing.org/content/282/1806/20150211

2. Why some nations have stopped growing?

https://www.nature.com/articles/pr2012189

https://www.newyorker.com/magazine/2004/04/05/the-height-gap

3. Speculations on the future

http://www.bbc.com/future/story/20150513-will-humans-keep-getting-taller