You are missing your course. Ask your teacher permission

Dear Mr Jones, How are you doing? I am Lucy, one of your student at your English center. I am writing to you my absence at your next lesson. As you know, I am a teacher at school. My collagues are going to have a rest at Chodak mountains on Friday from morning untill evening. I was not very eager to go there if my director, himself called me and invited to spend my day with them. I could not regret his invitation. I am terribly sorry that I will miss your lesson. After returning Chodak, I will contact with my coursemates who study at your center and ask the lesson and do my homework. I am looking forward to hearing from you. Yours sencerely, Mrs. Gulmira