height weight question?

i am a chinese guy just turned 21, and i know it's like impossible for me to grow and my father told me to build a healthy body (mascular body), my father is around the same height as me, he is around 62 kg, me on the other hand, is only 48 kg. however i realised i grow an additional 2 cm in the past few months, is it because i drank lots of milk after that, however, i simply look very skinny is it because i grow taller a bit, (i look even more skinny than before), wt can i do to be bigger, i am simply too skinny, and is it possible to grow taller after 20?? cause i realised i grow.