I am a 14 year old male , i wonder will i still grow ? im 5"11 now and my father is 5"7 and my mother is 5"3 but my grandfather is 6"1 ???

Maybe: The expected final height of males is the average of both parents + 2-3 inches. This places you above expected final height. Your parental height may have been reduced for a number of reasons given the grandfathers height, but that may not be the case. An x-ray of your wrist/hand could show if you still have potential to grow more.

You likely will : still grow in height. Most males will continue to gain height until 18 and some will still gain a little height up to age 20.