I like this girl, Very pretty, Have never talked to her. I am shy too, What to do? Help please!?

So there is this girl i like, She is very very pretty. I don't know what to do. I wanna ask her out but don't know how. I have her as a friend on Facebook and don't wanna ask her out there because it seems weird to ask someone out on FB. Im afraid to get turned down and this and that but who isn't. The other day she posted some pictures on Facebook and i saw a couple of them and mustered up the courage to Post a comment on the group of pictures and said "Dang you really Beautiful" I think i shouldn't of said that for it might of been weird. So this morning i sent her a direct message saying "Sorry(as the subject) Message: I hope what i wrote yesterday didn't weird you out. I was just speaking the truth, Sorry again if it did weird you out, Have a nice day :)" and i never got a reply and i have seen her online in my chat box and wondered if she got it. Before that like a couple of weeks ago i sent her a IM message on FB just saying "Just wanted to say Hi...Hi :)" and she never replyd. I'm really shy and it took a lot to even post and IM what i did to her on Facebook. (I literally sat there and procrastinated pressing the send button for i'd say 7-10 mins.) She also works at this sushi restaurant and she was serving me and my friend one time and i ordered a couple of rolls and one took way to long and i said " Oh can i get a box for this one i Ordered one to many, and could we get our check please?" and she brought the box and rang everything up and brought the check over. (Now with sushi and all you can eat, i got all you can eat, What ever pieces or rolls you don't eat they charge you extra) She said " here's your check and don't worry about the last roll." She didn't charge us and I've seen her charge other people before and not me, Which is way cool. So I'm wondering Does she like me? or just kindness. I do tip well and am not a chizzler. So what should i say? Should i have said what i said on Facebook? Any advice or tips would help soo much. Please help you guys and gals. Thank you everyone!