I am 21 years old now, and my height is 5 feet 4 inches, my father's height is 5 feet 8 inches, and my younger brother's height is 5 feet 11 inches, I am so surprise, I feel very ashamed when we together stand. I want to grow at least 4 inches. Can I?

Nope, as you've normally finished growing at this age.

No you are finished growing, and ashamed ? Why, all people are different heights.