Mental Block...I need help =[

So I'm trying to start my new story, the thing is I have the whole idea in my head whats gonna happen, you name it...everything is there but it wont come out...The reason why??? I dont know how to start the bloody story and it's driving me crazy.

I've tried jotting the start down, but nothing seems right and the worst of it all is I dont know how to fix it...So I wanna know if anyone has any ideas on how I can start my story, I cant even get the first sentence together, Nothing seems right and I guess I just want it to be perfect, every other story I've had I've been fine, but with this one I'm purely just stumped.

The first scene is set in a diner with the female (billie being the lead character) It's how she meets her future husband, the start of the pain she never saw coming...she serves a man who tries to hit on her and the male lead (aaron) swoops in and saves her and catches the jackass..telling him what was the bet to sleep with billie (Thats why the jerk was hitting on her) prior to that orders are being taken to waiting customers. (hope that's enough info if anyone can cell :-)

If anyone has any ideas how I can overcome this mental block it would be awesome if you could tell me :-)
well that's my lil rant I guess, LOL

peace!!!