im not an expert on girls, infact right now the picture of justin bieber is making me want to **** off in mothers bathroom.but i know girls are often into some "homosexual" moves. i.e. anal... but thats boring... like moves involving mouths and bums (mmm :P) anyway my luck goes out to you.
:)
just propose man, :)

take her somewhere with a special meaning to her, get down on one knee and tell her what she means to you, then ask.