My dad said he hit puberty when he was 19-20, i didn't believe that b'cos he is 6ft2, i haven't hit puberty and im 16+5ft? what do u think is happening?

Constitutional delay: There are some families where puberty & linear growth lag behind their age group. Some males do grow well into their early 20's. That said, i would want evidence from exam & tests that you fit into this category if you have no evidence of puberty at 16. In males increase in testicular size is the first sign. See your pcp for a workup including a bone age & blood tests.