It is possible, but not likely.
There is not a way for a 19 year to get any taller. At the age of 19 the body has reached it's full height.
no after age 21 the height is not increased.
by the age of 21, you have fully grown.
never
If I were you - I'd stop worrying about your height and enjoy your life ! At the age of 12, you're likely net even through puberty yet - so you'll be due a 'growth spurt' when that kicks in ! There is no pill, potion or device that can quickly make you gain height. The only way would be risky painfulsurgery - which, given your age - any reputable surgeon would refuse to do !
It is unlikely for a female to experience significant height gain after the age of 18-19, as growth plates typically close around this age. Any perceived increase in height could be due to posture changes or other factors.
There is not a way to get taller at the age of 19. I would try wear high heels to get taller.
No, you are done growing.
You need to take some healthy and nutritious food supplements and increase iron and zinc elements in your diet and except it you can also try unani medicine to increase height. In some cases it helps a lot. But age factor has a big impact on height gain. You can go here for more information http://www.drayurved.com/height-gain.php
It's possible but unlikely for a male to grow in height after age 20
It's possible. As you age, your metabolism slows down, which can lead to weight gain.
Possible yes probable no. Highly unusual after 18/19