How do I tell her I like her?

I have this friend who is my best friends younger sister(who is the same age as me). We weren't that close 2 years ago, but since last year or so we've been hanging out alot. I've always liked her but have been a bit shy in telling her, as I don't want to ruin our friendship. Here is a bit of background info: We get dinner 2,3, and somtimes 4 times per week. We always study together at the library after cles and we usually talk about our past relationships for hours....like 4 hours at a time.. We have a history where....she had been in an abusive relationship and where I had been in a relationship where I was cheated on. We both care about each other alot...we usually talk to each other on the phone a few times a week also. Now, I know guys tend to overthink things, but please give me some insight into a few things I've noticed. I always pay for her whenever we go out, I pick her up from her house and always make sure she makes it home safely. Whenever we do eat together, we share our food, and eat dessert out of the same plate all the time!!! We always look each other in the eyes when we are talking and sometimes smile, and she always dresses up when we go out. It gets a bit awkward when we get silent and look at each other. I met her older brother first and we are best of friends. Her older brother knows we hang out alot and is fine with it. Me and this girl, we skype with her brother time to time....he knows my family and I know his family. We've us 3 and my younger sister have gone on a mini vacations together too. So its not like he would stop me or anything. I would do anything in the world for her, and I take care of her as if she were my little sister. We both are sort of getting over our past relationships and I want to make sure that I am not just in and over my head with emotions. I love her but I dont want to ruin our friendship by telling her that I have strong feelings for her. Do all girls act like this with thier guy friends? I'm not sure how to tell her that I like her without her freaking out. For some reason I don't know if she likes me or not. Any Ideas.