Eminem

Yo... Hey!

Umm... I suppose everyone knows who Eminem is. I've been a big fan of Japanese music, but when I heard "Stan", I realized I really like Eminem. He's very cool and fresh! He has a strong personality and his music is very cool, it gives off a powerful feeling!
The lyrics of "Stan" are about one of Eminem's fans. Actually, I'm his biggest fan, just like Stan. I won't kill myself for Eminem though. Don't worry, that would be too crazy haha! 
Well... Since my English sucks so bad, I can't write anymore.

PS: His song is really good!

Nicely written :) You shouldn't say your English sucks though, it really doesn't! This would be a bit more casual way to write it (not being super-formal, more like how you'd talk to friends). You're doing very well, keep working at it! ^.^

Eminem

Yo...Hey! I suppose everyone knows who Eminem is. I was a big fan of Japanese music. But, when I heard "Stan", I started to really like Eminem because he is very cool! Fresh! He has a confident personality, and his music is powerful!

The lyrics of "Stan" tell a story about Eminem's fan . Actully, I am his biggest fan, just like Stan was, but I won't try to kill myself for Eminem. Haha, don't worry! That is too crazy.

P.S. His song is really good!

Good writing, Leo. Be confident in yourself! It's okay to make mistakes. Please don't say "My English sucks!" You're studying English, and every time you practice writing, you will make mistakes but you will learn more quickly.