One possible version：
Dear Peter,
I am Lihua, studying in Senior 3 of Xinhua High School, which you will visit. I am very happy for your homestay.
I like science subjects very much, especially maths. But my spoken English is so poor that I can’t communicate with foreigners fluently. Thank God you will come to help me with this problem. By the way, NBA is my favourite, so whenever I am free, I do watch it on TV. If only I could watch a live game in the USA!
Here I’d like to make some arrangements for our stay. Besides your team’s activities, I will show you around our city., and on the weekend we will go to Confucius’ home for a visit to experience some Chinese culture.
Of course, that’s what I want to do during your stay. What’s your opinion?
I am looking forward to getting your reply soon.
Yours,
LiHua