I want to improve my English,could you help me?

Let me introduce myself first, my name is Tiki an ordinary Chinese student,I'm interested in drawing and writing.My major is in art and I also write novel's in my spare time,I think I am working on my dream so I am always happy: )
Today is the start of my summer vacation and I will stay at home all day,although I have promised to myself that I will change in this summer vacation.Today is so hot in my hometown,so I decided to waste my time at home,just one day maybe: P
Ah,how to make this summer alot cooler?Just a joke: P
My brother always said I was so quiet,in fact i'm just not good at “big things” how can I explain this...For example,I can read in silence,I can write in silence,I can paint in silence,I can eat in silence,but I can't speak in public.I can't play the guitar in front others,I don't have enough courage to do big things like this.
Seriously,I'm really nervous now,because I'm not good at chatting in Enlish and I'm poor in grammar,I'm afraid to be strange,but I'd like to make progress rather than be strange,so if I do make a mistake,please help me to point out and correct.
thank you very much for reading this essay: )