I want to write a letter to my best friend, who is studying in another country since 10 month. I miss her very much.

Tomorrow i will have my final exams celebrations. I wish she could join, but i know it will not be possible, i want to write her It such a pity that the exams celebrations did not take place an a later date, because my missed best friend, would be of course welcome or because my missing friend or my best friend much missed by me or my still missed best friend. What is the best way to explain, that i wish she could be there because i miss her very much until now, even such a long time has passed since we have been studying together