Hi, this is my first post on these forums.
I'm in a similar situation, except I've known her for a year, we became close friends very quickly, and fell in love with each other over last summer. I suffer from chronic romantcism, while she is a complete commitment-phobe thanks to the way her last relationship (and a number previously) ended.
I'll probably talk about it more elsewhere, but anytime I get close to her heart, when she gets as soppy and dopey and in love with me as I am with her, but most frequently when I over do it with the romance and L words and the being-crazy-about-her stuff, she gets scared and retreats. It's bloody hard and this christmas I thought she'd got scared for the last time and was going to ask that we forget each other romantically.
On top of all this, she lives 600 miles, one sea and one country away until later this year!
Anyway, if I was in your situation, I'd seriously think about how she'll react, not everyone will agree with me on that, but depending on what kind of person she is, it might be worth giving her the time to get her head around how she's feeling. It will do yourself the world of good to give yourself time, chill out, and not get carried away. Make sure that if you do tell her, that you mean it, and will continue to mean it for a long time. She might be worth the short wait.
Once you know that you aren't just wild with an initial pasion which may fade, and that nothing will be lost if you tell her exactly how you feel, GOOD GOD MAN TELL HER. Let everything you feel out. Life is just far too short.