Writing a letter to my uncle to have his permission about visiting his computer factory

Dear my uncle,
Today, I write this letter to you and ask for permission to visit your computer factory. My class includes 29 students and we think your computer factory will help us have more knowlegde about information technology. We plan to be there on 5/11 at 8a.m and go to there on foot. Time staying in the factory will be 2 hours. As far as find out, your factory has many things for us to see and learn. So we want to visit which produce computer, funetonal room,...Knowing more about IT is also our purpose. If you don't mind, can you become guide for the visit for us? I'll be waiting for your reply.
~bang~