Move on buddy!!
wait.. is First love or Real love?
If is Real love and you cannot change her mind, the only thing you can do is continue with your life, I know it hurts but you must do it. Your life doesn't end there. Get another girl quickly because loneliness will kill you.
If it's First love, well don't worry buddy! move on! not always you will be with the first one forever. Later, You will find your soulmate