I'm 18, almost 19 and I still can't grow facial hair. I have armpit hair, leg hair, chest hair, everything but facial hair?

Facial hair is a genetic trait. If you're past your puberty years and you have no medical conditions, it is basically your genetic trait.  

Thanks for your question. Two things are important for young men to know about facial hair growth:Facial hair growth is strongly genetic. Some men, especially those of Mediteranean, Middle Eastern and men of the Indian subcontinent are more likely to grow thicker facial hair and have more hair compared to men of Northern European background. There are exceptions of course.Facial hair density and growth increases throughout the 20s and even into the 30s for some men. So the amount of facial hair you have at 18 is likely not the density you'll have at 28.Hair transplantation is an option for men to increase facial hair density - a trend that is increasingly popular.

Many young men want to accelerate their beard growth and ask
about it. It takes age (genetic triggers which occur in family lines) so
if you want to find out when your beard will grow out, you need to find out
when your father or grandfather started to grow theirbeard. Hormones should have kicked in
nicely by the time a man reaches 18 but he must wait out his genetics
as hormone alone are not responsible for the onset of beard grown. Beard
transplants can be done when the young man is a bit older (over 25) if the
beard has not grown in yet

Facial hair growth is genetic trait. It may take longer for some people to grow them out. At this point you need to be patient and give it a few more years.