I need everybody's opinon on this farewell meage Im writing to my ex?

If there has been no contact for 4 months then it's already over. I'm sorry to say this but the letter sounds as if you aren't over her at all. Think about it - what you've done is tell her you have a girlfriend, ped your exams and have a new life planned in the USA . In other words - who needs her? If your life is fabulous just enjoy it. Why bother to tell her? She has hurt you a lot - and it shows. Forget her and really get on with your life.