first, is 19 an old age to start to learn how to play the piano?
second, does anyone know where i can get free piano lessons online for free??
No age is too old to learn how to play the piano!
I am not familiar with free online piano lessons. I would suggest going to your local music store and asking if they can recommend a teacher. The benefit of having a teacher is that they can tell you what you are doing right and wrong. The best way to learn is from a hands on teacher.
If you don’t want to pay for weekly lessons, there are adult piano method books available. I would suggest the books if you have some music background. If you don’t know much about reading music, you might not know if what you are playing is correct.