I am 19 and half years old. can i increase my height?

No: You can make yourself taller. It is determined by genetics (parents). In fact, you are almost done with growing taller at this point.

Hard to say: Growth centers in long bones determine how tall you can grow.Most growth centers will close at 16-19 years in males. After that happens, you are done. If your growth centers are open, a balanced diet/rest ; healthy physical activity will support good growth.Their are no special diet or exercises that make you taller.