What to do?

[Hawkins]

It doesn't mean much actually. It just means that she uses facebook to interact with her closest people, and doesn't like comments. I think you should continue liking her statuses once in awhile, but not every single one.
Liking her statuses is enough for your online interaction with her. People tend to feel happier and please when their statuses get likes.

Now, be careful when you say hi to her at school though, eye contact is a very tricky thing. It can get you disliked by her, and deleted from facebook just like it can make her think that you seem like a nice guy.
I used to like a girl and we were ok on facebook but we pretty much never spoke at school, then one day she looked at me, I was pretty pissed off at the time and gave her a strange look, because I was surprised and I got 'butterflies' in my stomach, and that made me my day, but on the other hand, it made her feel unwanted and got me deleted from facebook, so I suggest you are careful with that. First impression is very important.