He is handsome. He is humorous. He is optimistic and he laughs a lot.
... very creative beginning ... impressive :)
he once beat a professional table tennis athlete
... I suggest "defeated" instead of "beat"
You have a beautiful flow up to this line;
Most of the intellectuals suffered a lot from the revolution but with his special background, he was treated extremely unfairly
Here you say many intellectuals were badly affected and so did your grandfather. Then why you used the word "but"? It tends to confuse the reader.
I, his granddaughter, did not hear of his whole story until I was twelve. When first told about the story, I was shocked.
... when you say "grandfather", the admission panel know that you are his granddaughter. So there's no need to tell that again; it only consumes your word count.
I was twelve when I first heard his shocking story.