One possible version:
I’m LiHua, an outgoing boy, who is studying in London. I am writing to apply to be a volunteer of your team, having heard that a Chinese Painting Exhibition will be held in this local city. I have some advantages for the job.
First of all, having lived in China for sixteen years and having learnt English since I was a child , I have a good command of English and Chinese, which is beneficial for introducing Chinese paintings. Besides, having a good knowledge of Chinese paintings because of my familiarity with Chinese painting culture, I can get foreigners and the locals to know more about it. Last but not least，through my introduction and efforts, I believe, I can strengthen the friendship between China and England. I would appreciate it if you could take my application into consideration.