Ms Lena..!
It might be hard to get a Pakistani Visa for a 23 years old girl. There is some kind of policy between Pakistan and China, not to issue pakistani visa for young chinese girls.
I couldnt get visa for my girlfriend last year they wouldnt give me a visa unless we were married> beacause a few years ago some chinese girls in pakistan did something which wasnt good for the image of china in pakistan so both governments made this policy.
but you can still try. you just need a pssport and an invitation letter from your friend who are pakistani or live in pakistan. and remember there is no visa fee for chinese nationals.