I don't get this girl?

I used to talk to this girl who had a crush on me and we were talking but when she was talking with me ,she was talking with this other guy ,and I guess she chose him over me and I knew this because she told my friend that she was talking to him and she wanted him to tell me that. So I pretty much backed off and I just ignored her comepletely.Now whenever I walk down the hallways I see her and she was always makes eye contact with me like she wants to say something,and a recently we were both at this cancer benefit and she took pictures of me while I was walkin with my friend.and she sent it to my other friend who was somewhere else,and she never talks to me but like she"ll like my stuff on facebook.She just confuses me.She also that type of girl who you have to msg first like all the time.Shes very outgoing and fun ,talks to alot of people.This all happened like when school was ending,and before she was official with the other guy.Should I of still tried?We literally have not talked in like 4 months.